#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
int n;
string s;

void solve(){
    sort(s.begin(),s.end());
    for(int i = 0;i<n-1;i++){
        if(s[i]==s[i+1]){
            cout<<"Yes"<<endl;
            return;
        }
    }
    cout<<"No"<<endl;
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> n;
    cin >> s;
    solve();
}