solids = [] $stdin.readlines.map { |line| line.strip.split(' -> ').map { |coord| coord.split(?,).map(&:to_i) } }.each { |path| (path.length - 1).times { |i| if path[i][0] == path[i+1][0] x = path[i][0] y1 = path[i][1] y2 = path[i+1][1] if y1 > y2 t = y2 y2 = y1 y1 = t end (y1..y2).each { |y| solids << [x, y] } else x1 = path[i][0] x2 = path[i+1][0] if x1 > x2 t = x2 x2 = x1 x1 = t end y = path[i][1] (x1..x2).each { |x| solids << [x, y] } end } } solids.uniq! maxy = solids.map{ |_, y| y }.max sands = 0 loop do sand = [500, 0] abyss = false loop do if solids.include?([sand[0], sand[1] + 1]) if solids.include?([sand[0] - 1, sand[1] + 1]) if solids.include?([sand[0] + 1, sand[1] + 1]) break else sand = [sand[0] + 1, sand[1] + 1] end else sand = [sand[0] - 1, sand[1] + 1] end else sand = [sand[0], sand[1] + 1] end if sand[1] > maxy abyss = true break end end if abyss break else solids << sand sands += 1 end end puts sands