#include <bits/stdc++.h>

#pragma GCC optimize("Ofast")
using namespace std;

void solve(int cs) {
  int n;
  cin >> n;
  cout << (n * 2 <= 100 ? "YES\n" : "NO\n");
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int tc = 1;
  // cin >> tc;
  for (int cs = 1; cs <= tc; cs++) {
    solve(cs);
  }
  return 0;
}