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

int cas,n,a[100005],b[100005],q[100005];

bool cmp(int x,int y){return(a[x]<a[y]);}
int main(){
    scanf("%d",&cas);
    while (cas--){
        scanf("%d",&n);
        int i;
        for (i=1; i<=n; i++) scanf("%d%d",&a[i],&b[i]);
        for (i=1; i<=n; i++) q[i]=i;
            sort(q+1,q+n+1,cmp);
            ll ans=0,tmp=0;int cnt=0;
        for (i=1; i<=n; i++) if (a[q[i]]>0){
            int bb=b[q[i]];
            while (bb--){cnt++;tmp+=a[q[i]];ans+=a[q[i]]*cnt;}
        }
        for (i=n; i; i--) if (a[q[i]]<=0){
            int bb=b[q[i]];
            while (bb--){
                if (tmp+a[q[i]]<=0)break;
                ans+=tmp+a[q[i]];tmp+=a[q[i]];
            }
            if (tmp<=a[q[i]])break;
        }
        printf("%I64d\n",ans);
    }
    return 0;
}