package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	depth := 0
	position := 0

	s := bufio.NewScanner(os.Stdin)
	for s.Scan() {
		tokens := strings.Split(s.Text(), " ")
		direction := tokens[0]
		value, _ := strconv.Atoi(tokens[1])
		switch direction {
		case "forward":
			position += value
		case "up":
			depth -= value
		case "down":
			depth += value
		}
	}

	fmt.Println(depth * position)
}