#include <bits/stdc++.h>
using namespace std;
int n, a[100009];
string s;
int f[26];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n >> s;
  if (n == 1) {
    cout << "Yes";
    return 0;
  }
  for (int i = 0; i < n; i++) {
    f[s[i] - 'a']++;
  }
  int flag = 0;
  for (int i = 0; i < 26; i++) {
    if (f[i] == 1) flag++;
  }
  if (flag == n) {
    cout << "No";
    return 0;
  }
  cout << "Yes";
  return 0;
}
