n, nmax = input().split()
chisla = input().split()

n = int(n)
nmax = int(nmax)
for i in range(len(chisla)):
    chisla[i] = int(chisla[i])

maxdobutok = 0

def fact(n):
    factorial = 1
    while n > 1:
        factorial *= n
        n -= 1
    return factorial

# def umozatel(dobutok, n):



sochetaniy = fact(n)//fact(n - nmax)//fact(nmax)

# for eaeao in range(sochetaniy):
#     for i in range(n):
#         for j in range(nmax):