use v6;

my $s = get();
chomp $s;
my @str = $s.split('');

my $count = 0;
my $long = 0;
my $keep = 0;
for @str -> $str {
	if $count > 0 {
		$long++;
	}

	if $str eq 'c' {
		$long  = 1;
		$count = 1;
	} elsif $str eq 'w' {
		if $count == 1 {
			$count++;
		} elsif $count == 2 {
			if $keep == 0 {
				$keep = $long;
			} elsif $long < $keep {
				$keep = $long;
			}
			$count = 0;
			$long = 0;
		}
	}
}

if $keep {
	say $keep;
} else {
	say "-1";
}

exit;