use strict;

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

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