package main

import . "fmt"
import . "slices"

func main() {
	var n int
	Scan(&n)
	a:=make([]int,n)
	for i:=range a {
		Scan(&a[i])
	}
	max:=Max(a)
	min:=Min(a)
	ans:=0
	if max>0 {
		ans+=max*2
	}
	if min<0 {
		ans-=min*2
	}
	Println(ans)
}