#include <vector> 
#include <list> 
#include <map> 
#include <set> 
#include <deque> 
#include <queue> 
#include <stack> 
#include <bitset> 
#include <algorithm> 
#include <functional> 
#include <numeric> 
#include <utility> 
#include <sstream> 
#include <iostream> 
#include <iomanip> 
#include <cstdio> 
#include <cmath> 
#include <cstdlib> 
#include <cctype> 
#include <string> 
#include <cstring> 
#include <ctime> 

using namespace std;

#define _int64 long long

_int64 a[2][110000];
_int64 b[2][110000];
int cnt[110000];
_int64 base;

bool pcmp(_int64 x,_int64 y)
{
  return (x&base)<(y&base);
}

int main()
{
  int i,l,t,n,j,x,y,now;
  _int64 ans,left,right,mid,tot;
  scanf("%d",&t);
  for (l=0;l<t;l++)
  {
    scanf("%d",&n);
    for (i=0;i<n;i++)
      #ifdef ONLINE_JUDGE
        scanf("%I64d",&a[0][i]);
      #else
        scanf("%lld",&a[0][i]);
      #endif
    for (i=0;i<n;i++)
      #ifdef ONLINE_JUDGE
        scanf("%I64d",&b[0][i]);
      #else
        scanf("%lld",&b[0][i]);
      #endif
    now=0;
    sort(a[0],a[0]+n);
    sort(b[0],b[0]+n);
    ans=0;
    base=(1LL<<61)-1;
    for (i=61;i>=0;i--)
    {
      /*
      if (i<=4)
      {
        cout<<base<<endl;
        for (j=0;j<n;j++)
          cout<<b[now][j]<<" ";
        cout<<endl;
      }
      */
      cnt[0]=0;
      for (j=0;j<n;j++)
      {
        cnt[j+1]=cnt[j];
        if ((b[now][j]&(1LL<<i))!=0) cnt[j+1]++;
      }
      tot=0;
      left=-1;right=0;
      for (j=n-1;j>=0;j--)
      {
        while ((right<n)&&((b[now][right]&base)+(a[now][j]&base)<(1LL<<i)))
        {
          left++;
          right++;
        }
        //cout<<"a: "<<a[j]<<" "<<left<<" "<<right<<endl;
        if ((a[now][j]&(1LL<<i))==0)
        {
          tot+=cnt[left+1];
          tot+=(n-right)-(cnt[n]-cnt[right]);
        }
        else
        {
          tot+=(left+1-cnt[left+1]);
          tot+=(cnt[n]-cnt[right]);
        }
      }
      //cout<<i<<" "<<tot<<endl;
      if (tot%2!=0) ans|=(1LL<<i);
      base/=2;
      left=-1;right=n;
      while (right-left>1)
      {
        mid=(left+right)/2;
        if ((b[now][mid]&(1LL<<(i-1)))!=0)
          right=mid;
        else left=mid;
      }
      j=0;
      x=0;y=right;
      while ((x<=left)||(y<=n-1))
      {
        if (x>left)
        {
          b[1-now][j]=b[now][y];
          j++;
          y++;
          continue;
        }
        if (y>n-1)
        {
          b[1-now][j]=b[now][x];
          j++;
          x++;
          continue;
        }
        if ((b[now][x]&base)<(b[now][y]&base))
        {
          b[1-now][j]=b[now][x];
          j++;
          x++;
        }
        else
        {
          b[1-now][j]=b[now][y];
          j++;
          y++;
        }
      }


      left=-1;right=n;
      while (right-left>1)
      {
        mid=(left+right)/2;
        if ((a[now][mid]&(1LL<<(i-1)))!=0)
          right=mid;
        else left=mid;
      }
      j=0;
      x=0;y=right;
      while ((x<=left)||(y<=n-1))
      {
        if (x>left)
        {
          a[1-now][j]=a[now][y];
          j++;
          y++;
          continue;
        }
        if (y>n-1)
        {
          a[1-now][j]=a[now][x];
          j++;
          x++;
          continue;
        }
        if ((a[now][x]&base)<(a[now][y]&base))
        {
          a[1-now][j]=a[now][x];
          j++;
          x++;
        }
        else
        {
          a[1-now][j]=a[now][y];
          j++;
          y++;
        }
      }
      now=1-now;
    }
    cout<<"Case #"<<l+1<<": "<<ans<<endl;
  }
  return 0;
}