#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
typedef long long ll;
const int maxv = 4e6 + 5;
typedef pair<ll, ll> pll;
typedef array<ll, 3> ar;
const ll lnf = 2e18;
const int inf = 2e9;
int mod = 1e9 + 7;

void solve()
{
    int n;
    cin>>n;
    vector<ll> a(n);
    for(auto &ai:a) cin>>ai;
    ll sum1 = 0;
    for(int i=0;i<n;i++){
        sum1+=abs(a[i]);
    }
    ll res=*min_element(a.begin(),a.end());
    ll cur=*max_element(a.begin(),a.end());
    if (cur < 0) cout << sum1 - 2ll * abs(cur) << '\n';
    else if (res >= 0) cout << sum1 - 2ll * res << '\n';
    else cout<< sum1 <<'\n';
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    cin >> t;
    while (t--)
    {
        solve();
    }
    return 0;
}