Pile

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//package cses5teht;

import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;

/**
 *
 * @author eamiller
 */
public class Cses5teht {
    
    
    public static void main(String[] args) {
        IO io = new IO();
        int n = io.nextInt();
        int[] taul = new int[n];
        
        for(int i=0; i<taul.length; i++) {
            taul[i] = io.nextInt();
        }
        
        
        if(taul.length <= 2) {
            System.out.println("Not a proof");
            return;
        }
        
        /*
        //hc koodi
        int pienin;
        for(int i=0; i<taul.length; i=asd(i)) {
            pienin = taul[i+1];
            for(int j = i+2; j<taul.length; j++) {
                if(taul[i]>taul[j] && pienin < taul[j]) {
                    System.out.println("Cheater");
                    return;
                } else if(taul[i]<taul[j]) {
                    i=j;
                    j++;
                    pienin = taul[i+1];
                } else if(taul[i]<pienin) pienin = taul[i];
            }
        }
        System.out.println("Not a proof");*/
        
        //vähä enemmän hc koodi
        int pienin;
        int i=0;
        pienin = taul[i+1];
        for(int j = i+2; j<taul.length; j++) {
            if(taul[i]>taul[j] && pienin < taul[j]) {
                System.out.println("Cheater");
                return;
            } else if(taul[i]<taul[j]) {
                i=j;
                j++;
                if(i<taul.length-1) pienin = taul[i+1];
            } else if(taul[j]<pienin) {
                pienin = taul[j];
            }
        }
        System.out.println("Not a proof");
    }
    
    public static int asd(int i) {
        int x=i+1;
        //while(x<taul.length && taul[i] > taul[x]) x++;
        return x;
    }
    
    
    
    
    public static class IO extends PrintWriter {
	private InputStreamReader r;
	private static final int BUFSIZE = 1 << 15;
	private char[] buf;
	private int bufc;
	private int bufi;
	private StringBuilder sb;
	
	public IO() {
		super(new BufferedOutputStream(System.out));
		r = new InputStreamReader(System.in);
		
		buf = new char[BUFSIZE];
		bufc = 0;
		bufi = 0;
		sb = new StringBuilder();
	}
	
	private void fillBuf() throws IOException {
		bufi = 0;
		bufc = 0;
		while(bufc == 0) {
			bufc = r.read(buf, 0, BUFSIZE);
			if(bufc == -1) {
				bufc = 0;
				return;
			}
		}
	}
	
	private boolean pumpBuf() throws IOException {
		if(bufi == bufc) {
			fillBuf();
		}
		return bufc != 0;
	}
	
	private boolean isDelimiter(char c) {
		return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f';
	}
	
	private void eatDelimiters() throws IOException {
		while(true) {
			if(bufi == bufc) {
				fillBuf();
				if(bufc == 0) throw new RuntimeException("IO: Out of input.");
			}
			
			if(!isDelimiter(buf[bufi])) break;
			++bufi;
		}
	}
	
	public String next() {
		try {
			sb.setLength(0);
			
			eatDelimiters();
			int start = bufi;
			
			while(true) {
				if(bufi == bufc) {
					sb.append(buf, start, bufi - start);
					fillBuf();
					start = 0;
					if(bufc == 0) break;
				}
				
				if(isDelimiter(buf[bufi])) break;
				++bufi;
			}
			
			sb.append(buf, start, bufi - start);
			
			return sb.toString();
		} catch(IOException e) {
			throw new RuntimeException("IO.next: Caught IOException.");
		}
	}
	
	public int nextInt() {
		try {
			int ret = 0;
			
			eatDelimiters();
			
			boolean positive = true;
			if(buf[bufi] == '-') {
				++bufi;
				if(!pumpBuf()) throw new RuntimeException("IO.nextInt: Invalid int.");
				positive = false;
			}
			
			boolean first = true;
			while(true) {
				if(!pumpBuf()) break;
				if(isDelimiter(buf[bufi])) {
					if(first) throw new RuntimeException("IO.nextInt: Invalid int.");
					break;
				}
				first = false;
				
				if(buf[bufi] >= '0' && buf[bufi] <= '9') {
					if(ret < -214748364) throw new RuntimeException("IO.nextInt: Invalid int.");
					ret *= 10;
					ret -= (int)(buf[bufi] - '0');
					if(ret > 0) throw new RuntimeException("IO.nextInt: Invalid int.");
				} else {
					throw new RuntimeException("IO.nextInt: Invalid int.");
				}
				
				++bufi;
			}
			
			if(positive) {
				if(ret == -2147483648) throw new RuntimeException("IO.nextInt: Invalid int.");
				ret = -ret;
			}
			
			return ret;
		} catch(IOException e) {
			throw new RuntimeException("IO.nextInt: Caught IOException.");
		}
	}
	
	public long nextLong() {
		try {
			long ret = 0;
			
			eatDelimiters();
			
			boolean positive = true;
			if(buf[bufi] == '-') {
				++bufi;
				if(!pumpBuf()) throw new RuntimeException("IO.nextLong: Invalid long.");
				positive = false;
			}
			
			boolean first = true;
			while(true) {
				if(!pumpBuf()) break;
				if(isDelimiter(buf[bufi])) {
					if(first) throw new RuntimeException("IO.nextLong: Invalid long.");
					break;
				}
				first = false;
				
				if(buf[bufi] >= '0' && buf[bufi] <= '9') {
					if(ret < -922337203685477580L) throw new RuntimeException("IO.nextLong: Invalid long.");
					ret *= 10;
					ret -= (long)(buf[bufi] - '0');
					if(ret > 0) throw new RuntimeException("IO.nextLong: Invalid long.");
				} else {
					throw new RuntimeException("IO.nextLong: Invalid long.");
				}
				
				++bufi;
			}
			
			if(positive) {
				if(ret == -9223372036854775808L) throw new RuntimeException("IO.nextLong: Invalid long.");
				ret = -ret;
			}
			
			return ret;
		} catch(IOException e) {
			throw new RuntimeException("IO.nextLong: Caught IOException.");
		}
	}
	
	public double nextDouble() {
		return Double.parseDouble(next());
	}
}

    

}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED