while (<$file2>) {
     chomp;
     my @fields = split /\s+/, $_;
     my $key = join "-", @fields[0..2];
     my ($start_date, $end_date) = @fields[5,6];
     my $start_day = (split /,/, $start_date)[2];
     my $end_day = (split /,/, $end_date)[2];
     my $duration = $end_day - $start_day + 1:
     my $corrected_duration = exists $free_days_left{$key}? $duration - $free_days_left{$key} : $duration;
     print $file3 join " ", $_, $duration, $corrected_duration, $corrected_duration * $unit_price, "\n";
}