package HashMap;

import java.util.HashMap;

import java.util.Scanner;

public class ClassCaptain {

public static Character solution1(int len, String inputString) {

Character result = null;

int maxVoteCount = 0;

HashMap<Character, Integer> voteInfo = new HashMap<>();

for (char c : inputString.toCharArray()) {

voteInfo.put(c, voteInfo.getOrDefault(c,0) + 1);

}

for (char c: voteInfo.keySet()) {

if (maxVoteCount < voteInfo.get(c)) {

maxVoteCount = voteInfo.get(c);

result = c;

}

}

return result;

}

public void main() {

Scanner in=new Scanner(System.in);

int len = in.nextInt();

String inputString = in.next();

System.out.print(solution1(len, inputString));

}

}