#include <iostream>
#include <list>

using namespace std;

int main(void){
  string s;
  cin >> s;

  int min = -1;
  list<int*> c;
  for(int i = 0; i < s.length(); i++){
    if(s[i] == 'c'){
      int *ci = new int[2];
      ci[0] = i; ci[1] = 0;
      c.push_back(ci);
    }else if(s[i] == 'w'){
      list<int*>::iterator it = c.begin();
      while( it != c.end() ){
        int *ci = *it;
        if(++ci[1] >= 2){
          min = i - ci[0] + 1 < min || min < 0 ? i - ci[0] + 1 : min;
          c.pop_front();
        }
		    ++it;
      }
    }
	}

  cout << min << endl;
  return 0;
}