mod = 1000000007
eps = 10**-9


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

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

    big = 0
    small = 0
    for a in A:
        if a > 50:
            big += 1
        elif a < 50:
            small += 1
    if big + small == 0:
        print(0)
    else:
        if big:
            print(pow(2, big + small - 1, mod))
        else:
            print(0)


if __name__ == '__main__':
    main()