#!/usr/bin/env ruby

@letters = {} 
data = File.read("data.txt")
data = data.split("\n")
data = data.map(&:chars)
data.each_with_index do |row, y|
  row.each_with_index do |letter, x|
    @letters[[x,y]] = letter
  end
end

found = 0

potential_starts = @letters.select{|key, val| val == "A" } 
potential_starts.each do |key, value| 
  score = 0

  if @letters[[key[0] - 1, key[1] - 1]] == "M" && @letters[[key[0] + 1, key[1] + 1]] == "S"
    score = score + 1
  end

  if @letters[[key[0] - 1, key[1] - 1]] == "S" && @letters[[key[0] + 1, key[1] + 1]] == "M"
    score = score + 1
  end

  if @letters[[key[0] + 1, key[1] - 1]] == "M" && @letters[[key[0] - 1, key[1] + 1]] == "S"
    score = score + 1
  end

  if @letters[[key[0] + 1, key[1] - 1]] == "S" && @letters[[key[0] - 1, key[1] + 1]] == "M"
    score = score + 1
  end

  found += 1 if score >= 2
end

p found