using namespace std;

#define REP(i,n) for(int i=0; i<n; ++i)

int N, M;

bool MyDataSortPredicate(const pair<int, int> l, const pair<int, int> r){
    return l.second < r.second;
}

int main(void)
{
    int t;
    cin >> t;
    while (t--)
    {
        cin >> N >> M;

        vector<vector<pair<int, int> > > data(M);

        REP(i, N){
            REP(j, M){
                int d1, d2;
                cin >> d1 >> d2;

                data[j].push_back(make_pair(d1, d2));
            }
            REP(j, M)
                sort(data[j].begin(), data[j].end(), MyDataSortPredicate);
        }

        int tmp = 0;
        int minVal = 10000 * 200;
        int pointRemained = 0;
        REP(i, M){
            while (data[i].size()){
                int d1 = data[i].back().first;
                int d2 = data[i].back().second;
                data[i].pop_back();

                if (d1 >= pointRemained) {
                    d1 -= pointRemained;
                    pointRemained = 0;
                }
                else {
                    d1 = 0;
                    pointRemained -= d1;
                }
                tmp += d1;
                pointRemained += d2;            
            }
            minVal = min(minVal, tmp);
            tmp = 0;
            pointRemained = 0;
        }
        cout << minVal << endl;
    }
}