#include<bits/stdc++.h>
using namespace  std;
using ll = long long;
 
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
 
    int x; cin >> x;
    if(x * 2 <= 100) {
        cout << "YES\n";
    } else {
        cout << "NO\n";
    }
    return 0;
}