using System;
using System.Collections.Generic;
class Program {
    static void Main() {
        string s = Console.ReadLine();
        List<int> cPosis = new List<int>();
        List<int> wPosis = new List<int>();
        int l = s.Length;
        for (int i = 0; i < l; i++) {
            if (s[i] == 'c') {
                cPosis.Add(i);
            } else if (s[i] == 'w') {
                wPosis.Add(i);
            }
        }

        int cC = cPosis.Count;
        int wC = wPosis.Count;
        int ans = 101;
        int w = 0;
        for (int c = 0; c < cC; c++) {
            for (; w < wC - 1 && wPosis[w] < cPosis[c]; w++) ;
            if (wC - 2 < w) break;
            int tmp = wPosis[w + 1] - cPosis[c] + 1;
            if (tmp < ans) ans = tmp;
        }
        if (ans == 101) ans = -1;
        Console.WriteLine(ans);
    }
}