with open("input/day10.txt") as f:
    size, input = 256, f.read().strip()

lengths = [int(i) for i in input.split(",")]

ring = list(range(size))
pos = 0
skip = 0

for length in lengths:
    assert length <= len(ring), "overlap undefined"

    tail = min(length, len(ring) - pos)
    head = max(length - tail, 0)

    a = pos + tail
    b = 0 + head

    prefix = ring[b:pos]
    inside = ring[pos:a] + ring[:b]
    suffix = ring[a:]

    assert length == len(inside)

    twisted = inside[::-1]

    ring = twisted[tail:] + prefix + twisted[:tail] + suffix
    pos = (pos + length + skip) % len(ring)
    skip += 1

print(ring[0] * ring[1])