#include <bits/stdc++.h>
using namespace std;
using ll = long long; 
#ifdef LOCAL
#include <debug.h>
#else
#define dbg(...) 0
#define dbgn(...) 0
#endif

int32_t main() {
    cin.tie(0)->sync_with_stdio(0);
    int n; 
    cin >> n; 
    int sum = 0; 
    for(int i = 0; i < n; i++){
        int x; 
        cin >> x; 
        sum += (x > 0); 
    }
    cout << (sum > 0 ? "Yes\n" : "No\n"); 
    return 0; 
}