mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline
    
    N = int(input())
    A = list(map(int, input().split()))

    ans = N * (N+1) // 2
    cnt = 0
    for a in A:
        if a == 0:
            ans -= cnt * (cnt + 1) // 2
            cnt = 0
        else:
            cnt += 1
    ans -= cnt * (cnt + 1) // 2
    print(ans)


if __name__ == '__main__':
    main()