#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
int N;
vector<ll> A;

void solve(){
    int iszero = 0;
    for(int i = 0; i < N; i++){
        if(A[i]<=1) iszero++;
    }
    if(iszero){
        cout<<"Yes"<<endl;
    }else{
        cout<<"No"<<endl;
    }
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> N;
    A.resize(N);
    for(ll i = 0; i < N; i++) cin >> A[i];
    solve();
}