import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
    public static void main(String args[] ) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String line = br.readLine();
        int min = 101;
        int index = 0;
        int index1;
        int index2;
		while ((index1 = line.indexOf("c", index)) != -1) {
        	index2 = line.indexOf("w", index1 + 1);
            if (index2 != -1) {
            	index2 = line.indexOf("w", index2 + 1);
            	if (index2 != -1) {
            		int len = index2 - index1 + 1;
            		if (min > len) {
            			min = len;
            		}
            	}
            }
            index++;
        }
		if (min == 101) {
			System.out.println("-1");
		} else {
			System.out.println(min);
		}
   }
}