use strict;
use warnings;

while( <> ) {
    chomp;
    # Test for validity of input, and capture significant digits.
    # If input seems invalid, die.
    unless( 
        m/^(?:2|42)   # Match but don't capture your prefix.
          (\d{11})\s  # Match and capture left-grouping of digits.
          (\d{13})\s  # Match and capture mid-grouping of digits.
          (\d3)/x     # Match and capture right-grouping of digits.
    ) { 
        die "Improperly formatted input data:\n\tLine: $.\t$_\n"; 
    }
    
    my( @columns ) = ( $1, $2, $3 );  # Retain the captures.
    
    # Look for "reject" codes.    
    next if $columns[1] =~ m/^\d{6}(?:406|408)\d{4}\s$/;
    
    # Print a nicely formatted result.
    print "CH $columns[0] $columns[1] $columns[2] LAB\n"; 
}