use strict;
use warnings;

while ( my $string = <DATA> ) {
    my $found = '';
    my $count = 0;
    chomp $string;
    if ( $string =~ /(5163)/g ) {
        $found .= $1;
        while ( $string =~ /([\d ])/g and $count < 8 ) {
            $found .= $1;
            if( $1 =~ /\d/ ) {
                $count++;
            }
        }
    }
    print +($count == 8 ) ? "$string\t=>\t$found\n"
                          : "$string\t\tFAILED:\ttoo few digits matched\n";
}


__DATA__
abcdef 5163 1234 5678
1234516323493293
12345163234932934567890
12345163234567