7

#!/usr/bin/perl/

use strict;

my (@seq, @seq1, @seq2, $distance);

@seq = <>;

# @seq1 = split //, chomp($seq[0]); # 这样会出错，chomp有返回值0 1

# @seq2 = split //, chomp($seq[1]);

@seq1 = split //, $seq[0];

@seq2 = split //, $seq[1];

for(my $i = 0; $i <= $#seq1; $i++){

        if($seq1[$i] ne $seq2[$i]){

                $distance++;

        }

}

print $distance."\n";

#!/usr/bin/perl

#

my @str = <STDIN>;

my $c = 0;

for ($i = 0; $i < length($str[0]); $i++){

        $c++ if (substr ($str[0], $i, 1)) ne (substr ($str[1], $i, 1));

}

print "$c\n";