#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<algorithm>
using namespace std;

struct node{
    int v,a;
}data[30];

bool cmp(node a,node b){
    return a.v>b.v;
}

int main(){
    int t;
    scanf("%d",&t);
    while(t--){
        int n,i,j;
        scanf("%d",&n);
        for(i=0;i<n;i++) scanf("%d%d",&data[i].v,&data[i].a);
        sort(data,data+n,cmp);
        int ans=0,upnum=0,downnum=0;
        if(data[0].v<=0) printf("0\n");
        else{
            for(i=0;i<n;i++){
                for(j=0;j<data[i].a;j++){
                    if(data[i].v>=0){
                        upnum+=data[i].v;
                        ans+=upnum-downnum;
                    }else{
                        downnum-=data[i].v;
                        if(downnum>=upnum) break;
                        ans+=upnum-downnum;
                    }
                }
                if(downnum>=upnum) break;
            }
            printf("%d\n",ans);
        }
    }
    return 0;
}