#include <iostream>
#include <vector>
#include <array>
using namespace std;

int main(void){

    int total_num;
    cin >> total_num;
    while (total_num) {
        int player_num, drafted_num;
        cin >> player_num >> drafted_num;

        array<int, 9> drafted_result = { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
        for (int i = 0; i < player_num; i++) {
            int pos, ability;
            cin >> pos >> ability;
            if (drafted_result.at(pos-1) < ability)
                drafted_result.at(pos-1) = ability;
        }

        int sum = 0;
        for (auto i : drafted_result)
            sum += i;
        cout << sum << endl;
        total_num--;
    }
    return 0;
}