#include <iostream>
using namespace std;
int main(){
	int n,k,s;
	long a;
	while(cin>>n>>k>>s){
		if(n==0&&k==0&&s==0) break;
		int h[k],t=0;
		h[0]=0;
		for(int i=0;i<k-1;i++){
			h[k-1-i]=n-i;
			t=t+n-i;
		}
		int ct=0;
		do{
			if(s-t<h[1]&&s-t>0){
				ct++;
			}
			for(int i=0;i<k-1;i++){
				if(h[i+1]-h[i]>1){
					h[i+1]--;
					break;
				}
				else if(h[i+1]-h[i]==1&&h[i+2]-h[i+1]>1){
					h[i+2]--;
					for(int j=0;j<i+1;j++){
						h[i+1-j]=h[i+2-j]-1;
					}
					break;
				}
			}
			t=0;
			for(int i=0;i<k-1;i++){
				t=t+h[i+1];
			}
		} while(t>(k-1)*k/2);
		if(k==1&&s<=n){
			cout<<1<<endl;
		}else{
			cout<<ct<<endl;
		}
	}
    return 0;
}