#include<iostream>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<ctime>
#define int long long
#define pii pair<int,int>
#define pb push_back
#define LL long long
#define mp make_pair
#define fi first
#define se second
using namespace std;
inline int read(){
    int f=1,ans=0; char c=getchar();
    while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
    while(c>='0'&&c<='9'){ans=ans*10+c-'0';c=getchar();}
    return f*ans;
}
const int MAXN=1e6+11;
int N,Sum,A[MAXN],cas; bool f1=0,f2=0;
signed main(){
    //freopen("1.in","r",stdin);
    cas=read(); while(cas--){
        f1=0,f2=1;
        N=read(); for(int i=1;i<=N;i++){
            A[i]=read(); 
            f2&=(A[i]<0);
            f1|=(A[i]<0);
        }
        //cerr<<f1<<" "<<f2<<endl;
        if(f1&f2){
            sort(A+1,A+N+1); Sum=0;
            for(int i=1;i<N;i++) Sum+=-A[i];
            printf("%lld\n",Sum+A[N]);
            continue;
        }
        if(f1){
            Sum=0; for(int i=1;i<=N;i++) Sum+=abs(A[i]);
            printf("%lld\n",Sum);
            continue;
        }
        Sum=0;
        sort(A+1,A+N+1); for(int i=1;i<=N;i++) Sum+=A[i];
        printf("%lld\n",Sum-2*A[1]);
    }
}