#!/usr/bin/env python

depth = 0
hPos = 0
aim = 0

with open('input') as f:
    window = []
    for line in f:
        cmd, numStr = line.split(" ", 2)
        num = int(numStr)

        # match...case is python 3.10+
        if cmd == "forward":
            hPos = hPos + num
            depth = depth + (aim*num)
        elif cmd == "backward":
            hPos = hPos - num
        elif cmd == "up":
            aim = aim - num
        elif cmd == "down":
            aim = aim + num
        else:
            raise "unknown command: "+cmd

print(depth * hPos)