#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <string>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#define X first
#define Y second
#define clr(u,v); memset(u,v,sizeof(u));
#define in() freopen("data","r",stdin);
#define out() freopen("ans","w",stdout);
#define Clear(Q); while (!Q.empty()) Q.pop();
#define pb push_back
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int maxn = 1e5 + 10;
const int INF = 0x3f3f3f3f;
pii N[100];
vector <int> V;
int sum[maxn];
int main()
{
    int T;
    scanf("%d", &T);
    while (T--)
    {
        V.clear();
        int n;
        scanf("%d", &n);
        for (int i = 0; i < n; i++)
        {
            scanf("%d%d", &N[i].X, &N[i].Y);
            while (N[i].Y--)
                V.pb(N[i].X);
        }
        sort(V.begin(), V.end());
        sum[V.size()] = 0;
        for (int i = V.size() - 1; i >= 0; i--)
            sum[i] = sum[i+1] + V[i];
        ll ans = 0, k = 1;
        //puts("");
        for (int i = 0; i < V.size(); i++)
            if (V[i] >= 0 || V[i] + sum[i+1] >= 0)
            {
                //cout<<V[i]<<" "<<k<<endl;
                ans += k * V[i];
                k++;
            }
        printf("%I64d\n", ans);
    }
    return 0;
}