#!/usr/bin/env perl

#   prime number calculation
# author: david@socialnerds.org

my $num = 3;
print "highest prime number: ";
chomp(my $maxnum = <STDIN>);
my $count = 2;

print "2\n3\n";

while ( $num <= $maxnum )
{
    $i=3;
    while ( $i <= int($num**(1/2)+1) )
    {
        if ( $i != 1 && $i < $num && $i%2 != 0 )
        {
            if ( $num % $i != 0 ) {
                $probably = "true"
            } else {
                $probably = "false";
                last;
            }
        }
        $i += 2;
    }

    if ( $probably eq "true" )
    {
        print "$num\n";
        $count++;
    }
    $num += 2;
}

print "prime number count: $count\n";