import java.util.*;
import java.lang.*;

class Main
{
	public static void main(String[] args) throws java.lang.Exception
	{
		String a = "zappaz";
        String b = "not";
        
        System.out.println(containsDouble(a, 'z'));
        System.out.println(containsDouble(b, 'z'));
	}
    
    private static boolean containsDouble(String s, char letter) {
        int firstIndex = s.indexOf(letter);

        return firstIndex > -1 && s.indexOf(letter, firstIndex + 1) > -1;
    }
}