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

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){
			System.out.println("-1");
			return;
		}

		int[] c = new int[100000];
		Arrays.fill(c, 0);

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

		for(int i = 0; i < max; i++){
			char chiwawa =line.charAt(i);
			if(chiwawa == 'c'){
				c[ccount]= i;
				ccount++;
			}
			if(chiwawa == 'w'){
				if(w > 0){
					check = true;
					for(int j = 0; j < ccount; j++){
						if(c[j] < w && min > i - c[j] + 1){
							min = i - c[j] + 1;
						}
					}
					w = i;
				}
				else
					w = i;
			}
		}

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

}