import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time,copy,functools

sys.setrecursionlimit(10**7)
inf = 10**20
eps = 1.0 / 10**10
mod = 998244353

def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def S(): return input()
def pf(s): return print(s, flush=True)


def main():
    rr = []

    while True:
        n,k,s = LI()
        if n == 0 and k == 0 and s == 0:
            break
        d = collections.defaultdict(int)
        d[(0,0)] = 1
        for i in range(1,n+1):
            for kk,vv in list(d.items()):
                if kk[0] == k or kk[1] + i > s:
                    continue
                d[(kk[0]+1,kk[1]+i)] += vv

        rr.append(d[(k,s)])

    return '\n'.join(map(str, rr))


print(main())


