#include <bits/stdc++.h>
using namespace std;
const int N = 1e6;
long long int ans, n, a[N];
string s;
int main() {
  cin >> n >> s;
  if (n == 1) {
    cout << "Yes";
    return 0;
  }
  for (int i = 0; i < n; i++) {
    a[s[i] - 'a']++;
  }
  for (int i = 0; i < 26; i++) {
    if (a[i] == 1) {
      ans++;
    }
  }
  if (ans == n) {
    cout << "No";
    return 0;
  }
  cout << "Yes";
  return 0;
}
