#include<cstdio>

 #include<iostream>

 int main() {

     int x,y,T,n;

     scanf("%d",&T);

     while(T--) {

         scanf("%d",&n);

         int A[] = {,,,,,,,};

         while(n--) {

             scanf("%d%d",&x,&y);

             std::swap(A[x],A[y]);

         }

         for(n = ;n<=;++n)

         if(A[n] == )

         break;

         printf("%d\n",n);

     }

 }