#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<vector>
#include<map>
#include<queue>
#include<string>
#include<sstream>
#include<cmath>
using namespace std;

int main(){

  string s;
  cin >> s;

  int cnt = 0;
  bool fl = false;
  int w = 0;
  for(int i=0; i<s.size(); i++){
    if( s[i] == 'c' ) fl = true;
    if( s[i] == 'c' && w == 0 ) cnt = 0;
    if( fl ) cnt++;
    if( fl && s[i] == 'w' ) w++;
    if( w == 2 ) break;
  }
  if( cnt != 0 && w == 2 ) cout << cnt << endl;
  else cout << -1 << endl;


  return 0;
}