# use strict;
# use warnings;

<>;
chomp(my $s = <>);
my @As = split(/\s/, $s);
my %d;
my %c;
foreach (@As) {
    next if exists($c{$_});
    if (exists($d{$_})) {
        delete $d{$_};
        $c{$_} = undef;
    } else {
        $d{$_} = undef;
    }
}
print(scalar(keys(%d)), "\n");