use strict;

chomp(my $s = <>);
chomp(my $t = <>);

my $c = 0;
if ($t =~ /^(.+)(\g1)$/) {
    while ($s =~ s/($1)($2)/\1.\2/) {
        $c++;
    }
} else {
    while ($s =~ /(\Q$t\E)/g) {
        $c++;
    }
}
if ($c && (length($t) == 1 || $t =~ /^\.+$/)) {
    print("-1\n");
} else {
    print($c, "\n");
}