#include <iostream>
#include <list>

using namespace std;

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

  int min = -1;
  list<int> c;
  bool wE = false;
  for(int i = 0; i < s.length(); i++){
    if(s[i] == 'c'){
      c.push_back(i);
    }else if(s[i] == 'w'){
      if(wE){
        int ci = *c.begin();
        c.pop_front();
        if(i - ci < min || min == -1){
          min = i - ci + 1;
        }
      }else if(c.size() > 0) wE = true;
    }
  }

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