#include <iostream>
using namespace std;
int main() {
  string a;
  cin >> a;
  int i, j, mojisu, min, wcnt;
  i = 0;
  mojisu = a.length();
  min = 999;
  while (i < mojisu - 2) {
    if (a.substr(i, 1) == "c") {
      wcnt = 0;
      j = i + 1;
      while (j < mojisu) {
        if (a.substr(j, 1) == "w") {
          wcnt++;
          if (wcnt == 2 && min > j - i + 1) {
            min = j - i + 1;
            break;
          }
        }
        j++;
      }
    }
    i++;
  }
  if (min == 999) {
    cout << -1 << endl;
  } else {
    cout << min << endl;
  }

  return 0;
}