#!/usr/bin/env luajit

local position, depth, aim = 0, 0, 0
for line in io.lines(arg[3]) do
	local split = line:find(" ")
	local direction = line:sub(1, split - 1)
	local value = line:sub(split + 1, -1)
	if direction == "forward" then
		position = position + value
		depth = depth + aim * value
	elseif direction == "up" then
		aim = aim - value
	else
		aim = aim + value
	end
end
print(depth * position)