#include<bits/stdc++.h>
using namespace std;
int n,m;
int s[3][100010];
void solve(){
    memset(s,0,sizeof(s));
    scanf("%d",&n);
    for(int i=1,x,y;i<=n;i++)scanf("%d %d",&x,&y),s[x][y]=1;
    int t=0;
    for(int i=1;i<=100000;i++)if(s[1][i])t=max(t,i+1);
    for(int i=1;i<=100000;i++)if(s[2][i]){
        if(s[1][i+1])t=max(t,i+3);
        else t=max(t,i+2);
    }
    cout<<t<<endl;
}
int main()
{
   int T; cin>>T; while(T--)solve();
   return 0;
}