#include <bits/stdc++.h>
using namespace std;
int cnt;
void countSet(int n, int k, int s) {
  if (k == 1 && s == n) {
    cnt++;
  } else if (s > n) {
    for (int i = n - 1; i > 0; --i) {
      countSet(i, k - 1, s - n);
    }
  }
}
int main() {
  int n, k, s;
  while (cin >> n >> k >> s, n) {
    cnt = 0;
    for (int i = n; i * k > s; --i) {
      countSet(i, k, s);
    }
    cout << cnt << endl;
  }
  return 0;
}
