#include <iostream>
#include <cmath>
#include<map>
using namespace std;

#define endl "\n"
#define int long long
/*
int prime(int a)
{
    int t = 0;
    for(int i = 2;i < a;i++)
    {
        if(a % i == 0)
        {
            t = a;
            break;
        }
    }
    return t;
}
*/
int32_t main()
{
    int x;
    cin>>x;
    if(x * 2 > 100)
    {
        cout<<"NO";
    }
    else
    {
        cout<<"YES";
    }
    return 0;
}