def equalStacks(h1, h2, h3):
    sum1, sum2, sum3 = sum(h1), sum(h2), sum(h3)
    i, j, k = 0, 0, 0
    
    while not (sum1 == sum2 == sum3):  
        if sum1 > sum2 or sum1 > sum3:
            sum1 -= h1[i]
            i += 1
        elif sum2 > sum1 or sum2 > sum3:
            sum2 -= h2[j]
            j += 1
        elif sum3 > sum1 or sum3 > sum2:
            sum3 -= h3[k]
            k += 1
        if i == len(h1) or j == len(h2) or k == len(h3):
            return 0
    return sum1

def equalStacks(h1, h2, h3):
    sum_h1, sum_h2, sum_h3 = sum(h1), sum(h2), sum(h3)
    
    while sum_h1 != sum_h2 or sum_h2 != sum_h3:
        if sum_h1 > sum_h2 or sum_h1 > sum_h3:
            sum_h1 -= h1.pop(0)
        elif sum_h2 > sum_h3:
            sum_h2 -= h2.pop(0)
        else:
            sum_h3 -= h3.pop(0)
    
    return sum_h1