mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    def comb(a):
        return a * (a-1) // 2

    N = int(input())
    A = list(map(int, input().split()))

    x = 0
    y = 0
    for a in A:
        if a == 1:
            x += 1
        elif a == 2:
            y += 1
    z = N - x - y
    ans = 2 * comb(x) + 3 * x * y + 2 * x * z + 1 * comb(y) + 1 * y * z + 1 * comb(z)
    print(ans)


if __name__ == '__main__':
    main()