#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B, X;
  cin >> A >> B >> X;
  int o = X - A;
  int M = B - o;
  if (X < A || X > B) {
    cout << "NO" << endl;
  }
  if (M + X == A + B) {
    cout << "YES" << endl;
  } else {
    cout << "NO" << endl;
  }
}
