#!/bin/python3
from functools import reduce
from itertools import combinations
import sys

import operator as op
def ncr(n, r):
    r = min(r, n-r)
    if r == 0: return 1
    numer = reduce(op.mul, range(n, n-r, -1))
    denom = reduce(op.mul, range(1, r+1))
    return numer//denom

def countArray(n, k, x):
    print(ncr(k,x))
    
    # Return the number of ways to fill in the array.

if __name__ == "__main__":
    n, k, x = input().strip().split(' ')
    n, k, x = [int(n), int(k), int(x)]
    answer = countArray(n, k, x)