#include <iostream>
#include <string>
using namespace std;

int main(void)
{
  int i, cou=0, w = 0, min = 200;
  string str;
  cin >> str;
  for(i=0;i<str.length();i++, cou++){
    if(str[i] == 'c'){
      cou = 1;
      w = 1;
    }
    if(str[i] == 'w' && w == 2){
      if(min>cou)min = cou;
    }
    if(str[i] == 'w' && w == 1)w = 2;
  }
  if(min!=200)cout << min << endl;
  else cout << "-1" << endl;
  return 0;
}