from collections import Counter
from math import factorial


def main():
    N = int(input())
    A = list(map(int, input().split()))
    counter_A = Counter(A)

    all_pattern_nums = factorial(N)
    for appear_num in counter_A.values():
        all_pattern_nums //= factorial(appear_num)

    print(all_pattern_nums)


if __name__ == "__main__":
    main()