#include <bits/stdc++.h>
using namespace std;
using ll = long long;

ll mod = 1e9 + 7;

int main()
{
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    ll t;
    cin >> t;
    while (t--)
    {
        ll n, m;
        cin >> n >> m;

        map<ll, vector<ll>> coins;
        for (int i = 0; i < m; i++)
        {
            ll d, v;
            cin >> d >> v;
            coins[d].push_back(v);
        }

        ll effi = n;
        ll ans = 0;
        priority_queue<ll> currCoins;

        for (int i = 0; i < n; i++)
        {
            for (auto i : coins[i + 1])
            {
                currCoins.push(i);
            }

            if (!currCoins.empty())
            {
                ll val = currCoins.top();
                currCoins.pop();
                ans += effi * val;
            }

            effi--;
        }

        cout << ans << "\n";
    }
    return 0;
}

//--------------------------------------------------------------------------------------

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

ll mod = 1e9 + 7;

int main()
{
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    ll t;
    cin >> t;
    while (t--)
    {
        ll n, m;
        cin >> n >> m;

        map<ll, vector<ll>> coins;
        for (int i = 0; i < m; i++)
        {
            ll d, v;
            cin >> d >> v;
            coins[d].push_back(v);
        }

        vector<pair<ll, vector<ll>>> coinsArray;
        for (auto i : coins)
        {
            coinsArray.push_back(i);
        }

        ll effi = n;
        ll ans = 0;
        priority_queue<ll> currCoins;
        for (int i = 0; i < coinsArray.size(); i++)
        {
            for (auto j : coinsArray[i].second)
            {
                currCoins.push(j);
            }

            if (i != coinsArray.size() - 1)
            {
                ll len = coinsArray[i + 1].first - coinsArray[i].first;
                ll reduceNum = 0;
                while (len && !currCoins.empty())
                {
                    ll curr = currCoins.top();
                    currCoins.pop();

                    ans += effi * curr;
                    effi--;
                    reduceNum++;
                    len--;
                }

                effi -= coinsArray[i + 1].first - coinsArray[i].first - reduceNum;
            }
        }

        ll leftLen = n - coinsArray[coinsArray.size() - 1].first + 1;
        while (leftLen && !currCoins.empty())
        {
            ll curr = currCoins.top();
            currCoins.pop();

            ans += curr * effi;
            effi--;
            leftLen--;
        }

        cout << ans << '\n';
    }
    return 0;
}