package main

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

func main() {
	var sum int
	in := bufio.NewScanner(os.Stdin)
	for in.Scan() {
		sum += diff(in.Text())
	}
	fmt.Println(sum)
}

func diff(l string) int {
	min, max := math.MaxInt64, 0
	for _, s := range strings.Split(l, "\t") {
		i, _ := strconv.Atoi(s)
		if min >= i {
			min = i
		}
		if max <= i {
			max = i
		}
	}
	return max - min
}