#include <iostream>
#include <string>
#include <algorithm>
#define INF 1000
using namespace std;

int main() {
  string s;
  cin >> s;
  int c = -1, w = -1, ans = INF;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == 'c' && c == -1) {
      c = i;
    } else if (s[i] == 'w') {
      if (c != -1 && w == -1) {
        w = i;
      } else if (c!= -1 && w != -1) {
        ans = min(ans, i - c + 1);
        c = w = -1;
      }
    }
  }
  cout << (ans != INF ? ans : -1) << endl;
  return 0;
}