#include <cstdlib>
#include <array>
#include <iostream>
#include <string>


int
main()
{
  std::cin.tie(0);
  std::ios::sync_with_stdio(false);

  std::string s;
  std::cin >> s;
  std::array<std::string::size_type, 3> ps{0, 0, 0};
  std::string::size_type pos = -1;
  int idx = 0;
  for (const auto& c : {'c', 'w', 'w'}) {
    if ((pos = s.find(c, pos + 1)) == std::string::npos) {
      std::cout << -1 << std::endl;
      return EXIT_SUCCESS;
    } else {
      ps[idx++] = pos;
    }
  }
  std::cout << (ps[2] - ps[0] + 1) << std::endl;

  return EXIT_SUCCESS;
}