#include <iostream>
#include<bits/stdc++.h>
using namespace std;
int arr[26];
int main(){
int n;
cin >> n;
string s;
cin >> s ;
for(int i = 0 ; i < n ;i++){
arr[s[i]-97] += 1;
}for(int i = 0 ;i < 26 ; i++){
if(arr[i] > 1 ){
cout << "Yes" ;
return 0;
}
}
cout << "No";
return 0;
}
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