#include <bits/stdc++.h>

using namespace std;

void test_case(int tc){
    int n, k;

    cin >> n >> k;

    vector<vector<int>> modulos(k);

    for(int i = 0; i < n; ++i){
        int s;
        cin >> s;

        modulos[s % k].push_back(s);
    }

    for(auto v : modulos){
        sort(v.begin(), v.end());
    }

    unsigned long long result = 0;

    for(int i = k - 1; i > 0; i--){
        while(!modulos[i].empty() && !modulos[k-i].empty()){
            int a = modulos[i].back(), b = modulos[k - 1].back();
            modulos[i].pop_back();
            modulos[k-1].pop_back();

            result += (a + b) / k;
        }
    }

    while(modulos[0].size() > 1){
        int a = modulos[0].back();
        modulos[0].pop_back();
        int b = modulos[0].back();
        modulos[0].pop_back();

        result += (a + b) / k;
    }

    for(int i = 0; i < k; ++i){
        for(int j = i + 1; j < k; ++j){
            while(!modulos[i].empty() && !modulos[j].empty()){
                int a = modulos[i].back(), b = modulos[j].back();
                modulos[i].pop_back();
                modulos[j].pop_back();

                result += (a + b) / k;
            }
        }
    }

    cout << result << '\n';

}



int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);

    int t;
    cin >> t;

    for(int tc = 1; tc <= t; ++tc){
        test_case(tc);
    }

    cout << flush;

    return 0;
}