Kyselyt

import java.util.Scanner;

public class kyselyt1 {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int amountOfCases = Integer.parseInt(in.nextLine());
		for (int i = 0; i < amountOfCases; i++) {
			System.out.println(performFunction(Integer.parseInt(in.nextLine())));
		}
		in.close();
	}

	public static char performFunction (int num) {
		int nd = (9 * (String.valueOf(num).length() + 1) * ((int) Math.pow(10, String.valueOf(num).length())) - ((int) Math.pow(10, String.valueOf(num).length() + 1)) + 1) /9; 
		
		int pos = String.valueOf(num).length() - ((nd - num) % String.valueOf(num).length());
		
		return String.valueOf(((int) Math.pow(10, String.valueOf(num).length())) - 1 - (int) Math.floor((nd - num) / String.valueOf(num).length())).charAt(pos - 1);
	}
}

Test 1

Group: 1

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 2
	at java.lang.String.charAt(String.java:658)
	at kyselyt1.performFunction(kyselyt1.java:18)
	at kyselyt1.main(kyselyt1.java:8)

Test 2

Group: 2

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 5
	at java.lang.String.charAt(String.java:658)
	at kyselyt1.performFunction(kyselyt1.java:18)
	at kyselyt1.main(kyselyt1.java:8)

Test 3

Group: 3

Verdict: RUNTIME ERROR

Exception in thread "main" java.lang.NumberFormatException: For input string: "672274832941907421"
	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
	at java.lang.Integer.parseInt(Integer.java:583)
	at java.lang.Integer.parseInt(Integer.java:615)
	at kyselyt1.main(kyselyt1.java:8)