#include<cstdio>
#include<algorithm>
#define ll long long
using namespace std;
int Read()
{
    int Output=0,W=1;
    char Input=getchar();
    while(Input<'0'||Input>'9')
    {
        if(Input=='-')W=-1;
        Input=getchar();
    }
    while(Input>='0'&&Input<='9')
    {
        Output=Output*10+Input-'0';
        Input=getchar();
    }
    return Output*W;
}
ll ABS(ll X)
{
    return (X>0?X:-X);
}
const int Inf=1e9+1;
int T;
int N;
ll Total;
ll Max=-Inf,Min=Inf;
int main()
{
    T=Read();
    while(T--)
    {
        Total=0,Min=Inf,Max=-Inf;
        N=Read();
        if(N==1)
        {
            printf("%d\n",Read());
            continue;
        }
        for(int i=1;i<=N;++i)
    {
        ll X=Read();
        Min=min(X,Min);
        Max=max(X,Max);
        Total+=ABS(X);
    }
    if(Min<0&&Max>0)printf("%lld",Total);
    else if(Max<=0)printf("%lld",Total-(ABS(Max)<<1));
    else printf("%lld",Total-Min*2);
    putchar('\n');
    }
}