Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		N, K, S := io.NextInt(), io.NextInt(), io.NextInt()
		if N == 0 {
			break
		}
		dp := [21][11][156]int{}
		for i := 0; i <= N; i++ {
			dp[i][0][0] = 1
		}
		for i := 1; i <= N; i++ {
			for j := 1; j <= K; j++ {
				for k := 1; k <= S; k++ {
					if k-i >= 0 {
						dp[i][j][k] += dp[i-1][j-1][k-i]
					}
					dp[i][j][k] += dp[i-1][j][k]
				}
			}
		}
		io.Println(dp[N][K][S])
	}
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := make([]interface{}, 0, len(a))
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := make([]interface{}, 0, len(a))
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

C++: #include <bits/stdc++.h>

#define LL long long
#define VI vector<int>
#define VVI vector<vector<int>>
#define VVVI vector<vector<vector<int>>>
#define VL vector<LL>
#define VVL vector<vector<LL>>
#define VVVL vector<vector<vector<LL>>>
#define VB vector<bool>
#define FOR(i,a,b) for(int i= (a); i<((int)b); ++i)
#define RFOR(i,a) for(int i=(a); i >= 0; --i)
#define FOE(i,a) for(auto i : a)
#define ALL(c) (c).begin(), (c).end()
#define RALL(c) (c).rbegin(), (c).rend()
#define DUMP(x)  cerr << #x << " = " << (x) << endl;
#define SUM(x) std::accumulate(ALL(x), 0LL)
#define MIN(v) *std::min_element(v.begin(), v.end())
#define MAX(v) *std::max_element(v.begin(), v.end())
#define EXIST(v,x) (std::find(v.begin(), v.end(), x) != v.end())
#define BIT(n) (1LL<<(n))
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end());
#define EPS 1e-14

template<class T> T ceil(T a, T b) { return (a + b - 1) / b; }
template<class T> void print(T x) { std::cout << x << std::endl; }

const std::string YES = "YES", Yes = "Yes", NO = "NO", No = "No";
const std::vector<int> dy = { 0, -1, 0, 1 }, dx = { 1, 0, -1, 0 };    // 4近傍（右, 下, 左, 上）

using namespace std;


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    while (true) {
        int N, K, S;
        cin >> N >> K >> S;
        if (N == 0 and K == 0 and S == 0) {
            break;
        }

        VVVI dp(N + 2, VVI(K + 2, VI(S + 2, 0)));
        dp[1][0][0] = 1;

        FOR(i, 1, N + 1) {
            FOR(j, 0, K + 1) {
                FOR(k, 0, S + 1) {

                    // not use
                    dp[i + 1][j][k] += dp[i][j][k];

                    // use
                    if (j + 1 < dp[0].size() and k + i <= S) {
                        dp[i + 1][j + 1][k + i] += dp[i][j][k];
                    }
                }
            }
        }

        print(dp[N + 1][K][S]);
    }
    return 0;
}

C++: //include
//------------------------------------------
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <fstream>
#include <complex>
#include <math.h>

using namespace std;

//conversion
//------------------------------------------
inline long toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
inline long toLong(string s) {long v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

//math
//-------------------------------------------
template<class T> inline T sqr(T x) {return x*x;}

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<long, long> PLL;
typedef long long LL;
//container util
//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,a,b) for(long i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

//constant
//--------------------------------------------

//clear memory
#define CLR(a) memset((a), 0 ,sizeof(a))

const long double EPS = 1e-6;
const long INF = 1e10;
int sum;
int dfs(int maxi,int ss,int cnt){
	if(cnt==0){
		if(ss==0)sum++;
		return 0;
	}
	for(int i=maxi;i>=1;i--){
		if(ss-i>=0)dfs(i-1,ss-i,cnt-1);
	}
	return 0;
}
int main(){
	int n,k,s;
	while(cin>>n>>k>>s){
		if(n==0&&k==0&&s==0)break;
		sum=0;
		dfs(n,s,k);
		cout<<sum<<endl;
	}
	return 0;
}

C++: // tsukasa_diary's programing contest code template
#include <bits/stdc++.h>
using namespace std;
// define
#define for_(i,a,b) for(int i=a;i<b;++i)
#define for_rev(i,a,b) for(int i=a;i>=b;--i)
#define allof(a) a.begin(),a.end()
#define minit(a,b) memset(a,b,sizeof(a))
#define size_of(a) (int)a.size()
// typedef
typedef long long lint;
typedef double Double;
typedef pair<int, int> pii;
//
typedef vector< int > Array;
typedef vector< Array > Matrix;
typedef vector< Double > DArray;
typedef vector< DArray > DMatrix;
typedef vector< string > SArray;
typedef vector< pii > PArray;
// popcount
inline int POPCNT(int _x) { return __builtin_popcount(_x); }
inline int POPCNT(lint _x) { return __builtin_popcountll(_x); }
// inf
const int iINF = 1L << 30;
const lint lINF = 1LL << 60;
// eps
Double EPS = 1e-9;
// in range
inline bool in_range(int _v, int _mx, int _mi) { return _mi <= _v && _v < _mx; }
inline bool in_range(Double _v, Double _mi, Double _mx) { return -EPS < _v - _mi && _v - _mx < EPS; }
inline bool in_range(int _x, int _y, int _W, int _H) { return 0 <= _x && _x < _W && 0 <= _y && _y < _H; }
// neighbor clockwise
const int DX[4] = {0,1,0,-1}, DY[4] = {-1,0,1,0};
const int DX_[8] = {0,1,1,1,0,-1,-1,-1}, DY_[8] = {-1,-1,0,1,1,1,0,-1};

int n, k, s;

int rec(int i, int prev, int sum) {
	if (sum > s) return 0;
	
	if (i == k) {
		if (sum == s) return 1;
		return 0;
	}
	
	int res = 0;
	
	for_(j,prev + 1, n + 1) {
		res += rec(i + 1, j, sum + j);
	}
	
	return res;
}

void solve() {
	cout << rec(0, 0, 0) << endl;
}

int main() {
	while (cin >> n >> k >> s, n) {
		solve();
	}
	return 0;
}