Still not clear what you mean by "first record", is "LA-03-2" and "LA-03-2" considered the same because the middle number "03" being the same, or the two numbers are numerically the same? Assuming the first: 
use strict;
my %seen;
while(<DATA>){
    chomp;
    my @parts = split /-/;
    print $_,"\n" if $parts[0] eq 'LA' && !$seen{$parts[0]-$parts[1]}+
++;
}

__DATA__
LA-1-00
CON-1-0
LA-2-01
LA-03-2
LA-03-02

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In reply to Re: How to get a value from a file and save in another file by sir.shz
in thread How to get a value from a file and save in another file by Anonymous Monk

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