From command-line argument. It's a fixed text file, in this case it only contains 4 lines but it can be thousands. The amount is always on that position on every line. The only way i could think of snatching them was through substr.

open IN, "<$ARGV[0]"
    or die "Could not open input file '$ARGV[0]' $!";
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Flat text file would be many lines of equal length with the amounts at that same position in every line.