#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll mod=998244353;



int main() {
    ll N;
    cin>>N;
    vector<ll> A(N);
    
    for(auto &a:A){
    	cin>>a;
        if(a<=1){
            cout<<"Yes"<<endl;
            return 0;
        }
    }
    cout<<"No"<<endl;
}