#include<algorithm>
#include<array>
#include<bitset>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<iomanip>
#include<iostream>
#include<map>
#include<numeric>
#include<queue>
#include<set>
#include<unordered_map>
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define endl '\n'
using namespace std;
using ll=long long;
using db=double;
using pii=pair<int,int>;
const int inf=0x3f3f3f3f;
const int mod=998244353;
const int N=1e6+10,M=1e3+10;
int a[N];
void solve()
{
    int n;
    cin >> n;
    for(int i=1;i<=n;i++)
        cin >> a[i];
    int maxa=*max_element(a+1,a+1+n),mina=*min_element(a+1,a+1+n);
    if(maxa<0||mina>0)
    {
        for(int i=1;i<=n;i++)
            a[i]=abs(a[i]);
        ll ans=0;
        for(int i=1;i<=n;i++)
            ans+=abs(a[i]);
        cout << ans-2*(*min_element(a+1,a+1+n)) << endl;
    }
    else
    {
        ll ans=0;
        for(int i=1;i<=n;i++)
            ans+=abs(a[i]);
        cout << ans << endl;
    }
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int t;
    cin >> t;
    while(t--)
        solve();
    return 0;
}