#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

int main() {
  string s;
  int ans = 101;
  cin >> s;
  for (size_t i = 0; i < s.length(); i++) {
    if (s[i] == 'c') {
      int tmp = 1, cnt = 1;
      for (size_t j = i + 1; j < s.length(); j++) {
        if (s[j] == 'w') {
          if (tmp == 1) {
            tmp = 2;
            cnt++;
          } else if (tmp == 2) {
            cnt++;
            ans = min(ans, cnt);
          }
        } else {
          cnt++;
        }
      }
    }
  }
  if (ans == 101) ans = -1;
  cout << ans << endl;
}