import itertools

N, K = map(int, input().split())
A = [i for i in input().split()]
ans = set()
for k in range(K,N+1):
    iter_A = itertools.combinations(A, k)
    for a in iter_A:
        tmp1 = '+'.join(a)
        tmp2 = '*'.join(a)
        ans.add(eval(tmp1))
        ans.add(eval(tmp2))

print(len(ans))