#include <iostream>
#include <bitset>

using namespace std;

int main(){
  int ans[21][11][156] = {0};
  int n, k, s;
  
  for(int i=1; i<(1<<20); i++){
    bitset<20> foo(i);
    if(foo.count() <= 10){
      int sum = 0;
      for(int j=0; j<20; j++)
	if(foo[j]==1)
	  sum+=(j+1);
      if(sum <= 155){
	int j = 19;
	while(foo[j] != 1)
	  j--;
	while(j<20){
	  ans[j+1][foo.count()][sum]++;
	  j++;
	}
      }
    }
  }
  
  while(cin >> n >> k >> s && n)
    cout << ans[n][k][s] << endl;   
  
  return 0;
}