#!/usr/bin/env luajit
require("utils")

local file = io.open(arg[3])
local prevchar = nil
local paircounts = {}
for char in chars(file:read("*l")) do
	if prevchar ~= nil then 
		paircounts[prevchar..char] = (paircounts[prevchar..char] or 0) + 1
	end
	prevchar = char
end

file:read("*l") -- skip empty line
local line = file:read("*l")
local rules = {}
while line ~= nil do
	rules[char(line, 1)..char(line, 2)] = char(line, 7)
	line = file:read("*l")
end

for step = 1, 10 do
	local npaircounts = {}
	for pair, count in pairs(paircounts) do
		if rules[pair] then
			local p1, p2 = char(pair, 1)..rules[pair], rules[pair]..char(pair, 2)
			npaircounts[p1] = (npaircounts[p1] or 0) + count
			npaircounts[p2] = (npaircounts[p2] or 0) + count
		else
			npaircounts[pair] = (npaircounts[pair] or 0) + count
		end
	end
	paircounts = npaircounts
	printtable(paircounts)
end

local charcounts = {}
for pair, count in pairs(paircounts) do
	charcounts[char(pair, 1)] = (charcounts[char(pair, 1)] or 0) + count
	charcounts[char(pair, 2)] = (charcounts[char(pair, 2)] or 0) + count
end
foreach(charcounts, function(v) return math.ceil(v / 2) end)
printtable(charcounts)

local min, max = math.huge, 0
for char, count in pairs(charcounts) do
	if count < min then min = count end
	if count > max then max = count end
end

print(max - min)