#include <bits/stdc++.h>
using namespace std;
int a, b, c, Max;
int main() {
  cin >> a >> b >> c;
  Max = max(a, max(b, c));
  if (a + b + c - Max >= Max) {
    cout << "YES\n";
  } else {
    cout << "NO\n";
  }
  return 0;
}
