Pile

import java.util.ArrayList;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author viljampa
 */
public class kilpa52 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
                // TODO code application logic here
        IO io = new IO();
        ArrayList<Integer> lista = new ArrayList();
        boolean onko = true;
        
        int montako = io.nextInt();
        for (int i = 0; i < montako; i++) {
            lista.add(io.nextInt());
        }
//        int montako = 3;
//        lista.add(3);
//        lista.add(1);
//        lista.add(2);
        
//        lista.add(1);
//        lista.add(2);
//        lista.add(7);
//        lista.add(8);
//        lista.add(9);
//        lista.add(6);
//        lista.add(5);
//        lista.add(4);
//        lista.add(3);

//        lista.add(3);
//        lista.add(2);
//        lista.add(1);
//        lista.add(4);
//        lista.add(5);
//        lista.add(6);
//        lista.add(8);
//        lista.add(9);
//        lista.add(7);
        
        
        int apu = lista.get(0);
        
        for (int i = 1; i < montako; i++) {
            int edel = lista.get(i - 1);
            int seur = lista.get(i);
            if (apu - 1 == seur || edel < seur) {
                if (apu - 1 == seur) apu = seur;
                if (seur > edel + 1) apu = seur;
            } else {
//                System.out.println(seur);
                onko = false;
            }
        }
        
        if (onko) {
            io.println("Not a proof");
        } else {
            io.print("Cheater");
        }
        
//        io.println();
//	String a = io.next(); // Lukee seuraavan välein erotellun merkkijonon.
//	int b = io.nextInt(); // Lukee seuraavan välein erotellun int-kokonaisluvun.
//	long c = io.nextLong(); // Lukee seuraavan välein erotellun long-kokonaisluvun.
//	double d = io.nextDouble(); // Lukee seuraavan välein erotellun double-liukuluvun.

        // Toimii kuten System.out.println.
//	io.println("Annoit syötteenä " + a + " " + b + " " + c + " " + d);
        io.close();
    }
    
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: ACCEPTED

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: ACCEPTED

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: ACCEPTED

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: ACCEPTED

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: ACCEPTED

Test 14

Verdict: WRONG ANSWER

Test 15

Verdict: ACCEPTED

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: ACCEPTED

Test 18

Verdict: WRONG ANSWER

Test 19

Verdict: ACCEPTED

Test 20

Verdict: WRONG ANSWER

Test 21

Verdict: ACCEPTED

Test 22

Verdict: WRONG ANSWER

Test 23

Verdict: ACCEPTED

Test 24

Verdict: WRONG ANSWER

Test 25

Verdict: ACCEPTED

Test 26

Verdict: WRONG ANSWER

Test 27

Verdict: ACCEPTED

Test 28

Verdict: WRONG ANSWER

Test 29

Verdict: ACCEPTED

Test 30

Verdict: WRONG ANSWER