#include <bits/stdc++.h>
using namespace std;
int main() {
  int p, c, a, b;
  cin >> a >> b >> p;
  c = a + b;
  if (((a > 500) || (b > 500)) && ((a >= 0) && (b >= 0))) {
    cout << "no";
    exit(1);
  }
  if (p <= c) {
    cout << "yes";
  } else {
    cout << "no";
  }
  return 0;
}
