import java.util.Scanner; public class Test3 { public static void main(String[] args) { Scanner scan=new Scanner(System.in); int n = scan.nextInt(); long[] arr=new long[n]; int a1=0,a2=0,a3=0; long min=2147483647; long sum=0; for(int i=0;i<n;i++){ arr[i]=scan.nextLong(); if(arr[i]>0){ a1=1; }else if(arr[i]<0){ a2=1; }else if(arr[i]==0){ a3=1; } if(min>arr[i]){ min=arr[i]; } sum=sum+Math.abs(arr[i]); } if(a3==1){ System.out.println(sum); return; } if(a1!=1||a2!=1){ sum=sum-Math.abs(min*2); } System.out.println(sum); } }