#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 1000000000000000001


int main(){
	int n;
	cin>>n;
	string s;
	cin>>s;
	sort(s.begin(),s.end());
	rep(i,s.size()-1){
		if(s[i]==s[i+1]){
			cout<<"Yes"<<endl;
			return 0;
		}
	}
	cout<<"No"<<endl;
	return 0;
}