#!/usr/bin/perl

$level=4;
$n=$ARGV[0];

if (scalar @ARGV == 2) {
  $level=$ARGV[1];
}


$bdry=0;
$intersize=0;

open IN, "all.nbd.xy.$level.txt";
while ($a=<IN>) {
#   print $a;
   @ll=split /\s+/,$a;
   if ($ll[1]==0 ||
       $ll[2]==0 ||
       $ll[3]==0 ||
       $ll[4]==0 ||
       $ll[5]==0 ||
       $ll[6]==0 
      ) {
      last;  
   }
   else { 
      $intsize++;
   }
}
close IN;

open IN, "all.nbd.xy.$level.txt";
# print "$intsize";
for ($i=1;$i<=($n-1)*$intsize;$i++) {
  $b=<STDIN>;
}
for ($i=1;$i<=$intsize;$i++) {
  $a=<IN>;
  chop $a;
  $b=<STDIN>;
  print "$a $b";
}
while ($a=<IN>) {
  chop $a;
  print "$a 0\n";
}