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

class No345 {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str = br.readLine();
		
		int CW = str.indexOf("cw");
		int C = 0; int W1 = 0; int W2 = 0;
		
		if (CW != -1)
			W2 = str.indexOf("w",CW+1);
		else {
			C =str.indexOf("c"); //cの位置
		    W1 = str.indexOf("w",C+1); //1つ目のwの位置
			W2 = str.indexOf("w",W1+1); //2つ目のwの位置
		}
		
		if (CW != -1 && W2 != -1) System.out.println( (W2 - CW) + 2);  //"cw"と"w"がある時
		else if (CW == -1 && C != -1 && W1 != -1 && W2 != -1 )  //"cw"がないが、cww全てが含まれる時
			System.out.println( (W2 - C) + 1 );
		else System.out.println(-1);
	}
}