#!/usr/bin/env python3
import re


def main():
    position = { 'distance': 0, 'depth': 0, 'aim': 0 }
    content = open('input', 'r').readlines()
    for line in content:
        move = line.strip()
        match = re.match('^(\w+) (\d+)$', move)
        direction, amount = match.groups(1)
        amount = int(amount)
        #print(f'logged: {direction} {amount} ')
        if direction == "forward":
            position['distance'] += amount
            position['depth'] += position['aim'] * amount
        elif direction == "down":
            position['aim'] += amount
        elif direction == "up":
            position['aim'] -= amount
    print(position['distance'] * position['depth'])


if __name__ == "__main__":
    main()