#include <bits/stdc++.h>

using namespace std;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  }
} initializer;

int main() {
  string s;
  cin >> s;
  int a = -1, b = -1, res = numeric_limits<int>::max();
  for (int i = 0; i < (int)s.size(); ++i) {
    if (s[i] == 'c') {
      a = i;
    } else if (s[i] == 'w') {
      if (b != -1) {
        res = min(res, i - b + 1);
      }
      if (a != -1) {
        b = a;
      }
    }
  }
  cout << (res != numeric_limits<int>::max() ? res : -1) << endl;
}