initial_string = [*0..255]
# initial_string = [*0..4]
shifts = File.open('puzzle_10.txt').read.split(',').map(&:to_i)
# shifts = [3, 4, 1, 5]
skip_size = 0
offset = 0
for shift in shifts do
    initial_string.rotate! offset
    if shift > 0 then
        rotated_bit = initial_string[0..shift - 1]
        kept_bit = initial_string[shift..initial_string.length-1]
        initial_string = rotated_bit.reverse + kept_bit
    end
    initial_string.rotate! -offset
    offset += shift + skip_size
    skip_size += 1
end
print initial_string[0] * initial_string[1]