#include <bits/stdc++.h>
#define int long long int
using namespace std;
void slv()
{
    int n;
    cin >> n;
    if(2*n>100)
    {
        cout<<"NO"<<endl ;
    }
    else
    cout<<"YES"<<endl;
}
int32_t main()
{
    std::ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

        slv();
}