#include <bits/stdc++.h>
using namespace std;

void solve() {
    int X;
    cin >> X;

    if (X * 2 <= 100)
        cout << "YES\n";
    else
        cout << "NO\n";
}

int main() {
    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif
    
    solve();

    return 0;
}