#!/usr/bin/env luajit

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