#include <bits/stdc++.h>
using namespace std;
const int N = 110000;
char a[N];
int chk[N];
int main() {
  ios_base::sync_with_stdio(0);
  int n;
  cin >> n;
  cin >> a;
  if (n == 1) {
    cout << "Yes" << endl;
    return 0;
  }
  for (int i = 0; i < n; i++) chk[a[i]]++;
  bool flg = 1;
  for (int i = 0; i < 256; i++) {
    if (chk[i] != 1 && chk[i] != 0) flg = 0;
  }
  if (flg)
    cout << "No" << endl;
  else
    cout << "Yes" << endl;
  return 0;
}
