def equalStacks(h1, h2, h3):
    s1, s2, s3 = sum(h1), sum(h2), sum(h3)
    h1.reverse()
    h2.reverse()
    h3.reverse()
    while True:
        minimum = min(s1, s2, s3)
        if not minimum:
            return minimum
        s1 -= h1.pop() if s1 > minimum else 0
        s2 -= h2.pop() if s2 > minimum else 0
        s3 -= h3.pop() if s3 > minimum else 0
        if s1 == s2 == s3:
            return s1