import java.util.Scanner;

public class Test {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		String s = sc.next();
		int a, b, c, min = 1000;
		a = s.indexOf('c');
		while(a >= 0){
			b = s.indexOf('w', a);
			c = s.indexOf('w', b+1);
			min = Math.min(min, c-a+1);
			a = s.indexOf('c', a+1);
		}
		if(min < 1000){
			System.out.println(min);
		} else {
			System.out.println(-1);
		}
	}
}