#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, s, ans, t, u;
  while (cin >> n >> k >> s, n) {
    int A[k];
    if (k == 1) {
      if (n >= s)
        cout << 1 << endl;
      else
        cout << 0 << endl;
    }
    for (int i = 0; i < k - 1; ++i) A[i] = i + 1;
    A[k - 1] = s - k * (k - 1) / 2;
    ans = 0;
    t = k - 2;
    while (A[k - 1] > A[k - 2]) {
      if (A[k - 1] <= n) ++ans;
      ++A[t];
      --A[t + 1];
      if (A[t] >= A[t + 1]) {
        while (t > 0) {
          --t;
          ++A[t];
          u = 0;
          for (int i = 0; i <= t; ++i) u += A[i];
          for (int i = t + 1; i < k - 1; ++i) {
            A[i] = A[i - 1] + 1;
            u += A[i];
          }
          A[k - 1] = s - u;
          if (A[k - 1] > A[k - 2]) {
            t = k - 2;
            break;
          }
        }
        if (!t) break;
      }
    }
    cout << ans << endl;
  }
  return 0;
}
