#!/usr/bin/env python3

lines = (x.strip() for x in open("input.txt"))

hor = 0
depth = 0
aim = 0
for line in lines:
    cmd, strVal = line.split(" ")
    val = int(strVal)
    if cmd == 'forward':
        hor += val
        depth += aim * val
    elif cmd == 'down':
        aim += val
    else:
        aim -= val

print(hor*depth)