#include<bits/stdc++.h>
#define debug(x) cerr<<#x<<" = "<<x
#define sp <<"  "
#define el <<endl
#define fgx cerr<<"-----------------------------------"<<endl
#define LL long long
#define DB double
#define pb push_back
#define LDB long double
using namespace std;
inline LL read(){
    LL nm=0; bool fh=1; char cw=getchar();
    for(;!isdigit(cw);cw=getchar()) fh^=(cw=='-');
    for(;isdigit(cw);cw=getchar()) nm=nm*10+(cw-'0');
    return fh?nm:-nm;
}
#define M 100050
int n,ans,mx,ht,x11,x12,x21,x22;
int hv1[M],hv2[M];
inline int solve(){
    n=read(),ht=mx=ans=0,memset(hv1,0,sizeof(hv1)),memset(hv2,0,sizeof(hv2));
    for(int x,y,i=1;i<=n;i++) x=read(),y=read(),(x==1)?(hv1[y]=1):(hv2[y]=1),mx=max(mx,y);
    while(true){
        if(ht>=mx&&!x11&&!x12&&!x21&&!x22) break; ans++,ht++;
        x11=x12=0;
        if(x22) x12=1,x22=0;
        if(hv1[ht]) x11=1;
        if(x21){
            if(!x11) x11=1,x21=0;
            else x22=1,x21=0;
        }
        if(hv2[ht]) x21=1;
    } return ans;
}
int main(){
    for(int Cas=read();Cas;--Cas) printf("%d\n",solve());
    return 0;
}