#include<bits/stdc++.h>
using namespace std;
#define int long long
#define fer(i,a,b) for(int i=a;i<=b;i++)
#define fdr(i,a,b) for(int i=a;i>=b;i--)
const int N=1e6+10; 
const int INF=1e9+10;

int n;
int a[N];
signed main(){
	ios::sync_with_stdio(0);cin.tie(0),cout.tie(0);
	int t;
	cin>>t;
	while(t--){
		cin>>n;
		int f=0,ff=0;
		int sum=0;
		int mn=INF;
		fer(i,1,n){
			cin>>a[i];
			if(a[i]<0) f=1;
			if(a[i]>=0) ff=1;
			sum+=abs(a[i]);
			mn=min(mn,abs(a[i]));
		}
		if(f){
			if(!ff) cout<<sum-2*mn<<endl;
			else cout<<sum<<endl;
		}
		else{
			cout<<sum-2*mn<<endl;
		}
	}		
}


//5
//4
//1 -3 2 -4
//11
//91 66 73 71 32 83 72 79 84 33 93
//12
//91 66 73 71 32 83 72 79 84 33 33 93
//13
//91 66 73 71 32 83 72 79 84 33 33 33 93
//1
//0