#!/usr/bin/env ruby

data = File.read("data.txt")

data = data.split("\n")
data = data.map(&:split)

safe_arr = data.map do |row|
  directions = []

  row.each_with_index do |value, index|
    next if index.zero?
    distance = (value.to_i - row[index-1].to_i)
    direction = if (distance.abs > 3 )
                  :err
                elsif distance > 0
                  :up
                elsif distance  < 0
                  :down
                else
                  :err
                end

    directions << direction
  end

  directions.uniq.count == 1 ? 1 : 0


end

p safe_arr.sum