#include <bits/stdc++.h>
using namespace std;
int x[100][1000][250], a, b, c, i, j, k, l, sum;
int main() {
  while (true) {
    sum = 0;
    memset(x, 0, sizeof(x));
    cin >> a >> b >> c;
    if (a == 0) {
      break;
    }
    x[0][0][0] = 1;
    for (i = 1; i <= b; i++) {
      for (j = 0; j <= c; j++) {
        for (l = 0; l < a; l++) {
          for (k = l + 1; k <= a; k++) {
            x[i][j + k][k] += x[i - 1][j][l];
          }
        }
      }
    }
    for (i = 0; i <= a; i++) {
      sum += x[b][c][i];
    }
    cout << sum << endl;
  }
}
