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

    all_patterns = N * (N+1) // 2
    current_length = 0
    patterns_1 = 0
    for A_elm in A:
        if A_elm == 1:
            current_length += 1
        else:
            patterns_1 += current_length * (current_length + 1) // 2
            current_length = 0
    patterns_1 += current_length * (current_length + 1) // 2
    print(all_patterns - patterns_1)


if __name__ == "__main__":
    main()