#include <bits/stdc++.h>
using namespace std;
const int C = 26;
int apps[C];
int main() {
  int n;
  cin >> n;
  string str;
  cin >> str;
  for (int i = 0; i < n; ++i) {
    ++apps[str[i] - 'a'];
  }
  int ones = 0;
  for (int c = 0; c < C; ++c) {
    if (apps[c] == 1) ++ones;
  }
  if (n > 1 && ones == n) {
    cout << "No\n";
  } else {
    cout << "Yes\n";
  }
}
