/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		for(int i=0;i<t;i++){
			int n = sc.nextInt()-1;
			int sum = 0;
			for(int j=0;j<n;j++){
				sum=sum+sc.nextInt();
			}
			System.out.println(0-sum);
		}
	}
}

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Mgo0CjMgLTQgNQoxMQotMzAgMTIgLTU3IDcgMCAtODEgLTY4IDQxIC04OSAw

2
4
3 -4 5
11
-30 12 -57 7 0 -81 -68 41 -89 0