import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {

    void solve() throws IOException {
        String s = ns();
        int w1 = -1;
        int w2 = -1;
        int ans = Integer.MAX_VALUE;

        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == 'w') {
                w1 = w2;
                w2 = i;
            } else if (s.charAt(i) == 'c') {
                if (w1 != -1) {
                    ans = Math.min(ans, w1 - i + 1);
                }
            }
        }

        if (ans == Integer.MAX_VALUE) {
            out.println(-1);
        } else {
            out.println(ans);
        }
    }

    String ns() throws IOException {
        while (!tok.hasMoreTokens()) {
            tok = new StringTokenizer(in.readLine(), " ");
        }
        return tok.nextToken();
    }

    int ni() throws IOException {
        return Integer.parseInt(ns());
    }

    long nl() throws IOException {
        return Long.parseLong(ns());
    }

    double nd() throws IOException {
        return Double.parseDouble(ns());
    }

    static BufferedReader in;
    static PrintWriter out;
    static StringTokenizer tok;

    public static void main(String[] args) throws IOException {
        in = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);
        tok = new StringTokenizer("");
        Main main = new Main();
        main.solve();
        out.close();
    }
}