#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;
const int N = (int)5e5 + 7, MOD = (int)1e9 + 7;
int n, m;
bool ok = 0;
string second;
map<char, bool> mp;
int main() {
  ios_base ::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n;
  if (n == 1) {
    ok = 1;
  }
  cin >> second;
  for (int i = 0; i < (int)second.size(); i++) {
    if (mp[second[i]] == 1) ok = 1;
    mp[second[i]] = 1;
  }
  if (ok)
    cout << "Yes"
         << "\n";
  else
    cout << "No"
         << "\n";
  exit(0);
}
