> var
>         a:array[1..10000] of longint;
>         i,j,n,t,x,y,k:longint;
>         b:array[1..10000] of boolean;
> begin
>         readln(t);
>         for i:=1 to 10000000 do
>                 inc(t);
>         for i:=1 to 10000000 do
>                 dec(t);
>         for i:=1 to t do
>         begin
>                 fillchar(a,sizeof(a),0);
>                 readln(n);
>                 for j:=1 to n-1 do
>                 begin
>                         readln(x,y);
>                         a[y]:=x;
>                 end;
>                 readln(x,y);
>                 fillchar(b,sizeof(b),false);
>                 b[x]:=true;
>                 repeat
>                         k:=x;
>                         b[k]:=true;
>                         x:=a[k];
>                 until x=0;
>                 repeat
>                         k:=y;
>                         if b[k] then
>                         begin
>                                 writeln(k);
>                                 break;
>                         end
>                         else
>                                 b[k]:=true;
>                         y:=a[k];
>                 until y=0;
>         end;
> end.