#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::string::size_type pos = -1;
  if ((pos = s.find('c', pos + 1)) == std::string::npos) {
    std::cout << -1 << std::endl;
    return EXIT_SUCCESS;
  } else {
    while (pos + 1 < s.length() && s[++pos] == 'c');
    pos--;
  }

  std::array<std::string::size_type, 3> ps{pos, 0, 0};
  int idx = 1;
  for (const auto& 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;
}