#include <bits/stdc++.h>
using namespace std;
int fv[10010];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int n;
  cin >> n;
  string s;
  cin >> s;
  int ans = 0;
  int dif = 0;
  for (auto &x : s) {
    fv[x]++;
    if (fv[x] == 1) {
      dif++;
    }
    if (fv[x] > 1) {
      ans = 1;
    }
  }
  if (dif == 1) {
    ans = 1;
  }
  if (ans) {
    cout << "Yes";
  } else {
    cout << "No";
  }
  return 0;
}
