from collections import *

N = int(input())
S = input()
if N == 1:
    print(1)
elif N == 2:
    print(len(set(S)))
else:
    C = Counter(S)
    ans = [0] * 40

    def check(C, i):
        temp = Counter(str(i))
        for k, v in temp.items():
            if v > C[k]:
                return 0
        return 1

    for i in range(111,1000):
        if check(C, i):
            ans[i%40] = 1
    print(sum(ans))