#include<bits/stdc++.h>
#define ll    long long int
#define yes   "YES"
#define no    "NO"
#define nl    "\n"
using namespace std;

void solve()
{
    int n;
    cin>>n;
    vector<int>a(n);
    for(int i=0; i<n; i++)
    {
        cin>>a[i];
    }
}

int main()
{
    int n;
    cin>>n;
    if(n*2<=100)cout<<yes<<nl;
    else cout<<no<<nl;
    return 0;
}