#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
using mint = atcoder::modint998244353;
using maxt = atcoder::modint1000000007;

int main() {
  int N;
  string S;
  cin >> N >> S;
	bool ans = false;
	for(int i = 0; i < N; i++) {
	  for(int j = i + 1; j < N; j++) {
	    if(S.at(i) == S.at(j)) {
	      ans = true;
	    }
	  }
	}
	if(ans) {
	  cout << "Yes" << endl;
	}
	else {
	  cout << "No" << endl;
	}
}