def surfaceArea(A):
    cubemap = set()
    tot = 0
    for i in range(len(A)):
        for j in range(len(A[0])):
            for k in range(A[i][j]):
                tot += 6
                # check if any of the 6 adjacent spaces are occupied
                # remove 2 for each shared face
                cord = [i, j, k]
                for a in range(3):
                    for b in range(-1, 2, 2):
                        cord[a] += b
                        if tuple(cord) in cubemap:
                            tot -= 2
                cubemap.add((i, j, k))
    return tot