use warnings;
use strict;

use constant kMaxGap => 7;

my @gappyData;

/^(\d+)\s+(\d+)/ and $2 != 0 and $gappyData[$1] = $2 while <DATA>;

my $lastx;
my $lasty;
my $currx = 1;

for (@gappyData[1..$#gappyData]) {
    next if ! defined $lastx;
    next if ! defined $lasty;

    my $gap = $lastx - $currx - 1;
    
    next if $gap == 1;
    next if $gap > kMaxGap;
    next if ! defined $gappyData[$currx] or $gappyData[$currx] != $lasty;
    $_ = $lasty for @gappyData[$lastx .. $currx];
} continue {
    $lasty = $_, $lastx = $currx if defined $_;
    ++$currx;
}

$currx = 1;
for (@gappyData[1..$#gappyData]) {
    if (defined $_) {
        print "$currx, $_\n";
    } else {
        print "$currx, -\n";
    }
    ++$currx;
}