1 #include<stdio.h>
 2 #include<queue>
 3 using namespace std;
 4 struct Node{
 5     int position,dis;
 6     friend bool operator < (Node a,Node b){
 7         if(a.position!=b.position)return a.position>b.position;
 8         else return a.dis>b.dis;
 9     }
10 };
11 int main(){
12     int T,N,k;
13     Node m;
14     scanf("%d",&T);
15     while(T--){k=0;priority_queue<Node>stone;
16         scanf("%d",&N);
17         while(N--)scanf("%d%d",&m.position,&m.dis),stone.push(m);
18         while(!stone.empty()){k++;
19             if(k&1)m=stone.top(),m.position+=m.dis,stone.push(m);
20             stone.pop();
21             if(stone.empty())printf("%d\n",stone.top().position);
22         }
23     }
24     return 0;
25 }