#include<stdio.h>
 #include<string.h>
 char people[101][21];
 int main()
 {
  int T,n,i;
  char str[21];
  scanf("%d",&T);
  while(T-->0)
  {
scanf("%d",&n);
getchar();
scanf("%s",str);
for(i=1;i<=n;i++)
scanf("%s",people[i]);
for(i=1;i<=n;i++)
if(strcmp(str,people[i])==0)
{
break;
}
if(i<=n/2)
printf("%s\n",people[n/2+i]);
else
  printf("%s\n",people[i-n/2]);
  }
  return 0;
 }