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

public class QuestionA {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		String line;

		try{
			line = in.readLine();
		}catch(IOException e){
			line = "";
		}

		int min = line.length();
		int c = 0;//直前のcの位置
		int w = 0;//直前のwの位置
		boolean check = false;

		for(int i = 0; i < line.length(); i++){
			if(line.charAt(i) == 'c')
				c = i;
			if(line.charAt(i) == 'w'){
				if(c < w){
					check = true;
					if(min > i - c + 1)
						min = i - c + 1;
					w = i;
				}
				else
					w = i;
			}
		}

		if(check) System.out.println(min);
		else System.out.println("-1");
	}

}