#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <sstream>
#include <complex>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <cmath>
#include <typeinfo>
#include <cassert>
#include <fstream>
#define REP(i,n) for(int i=0;i<n;i++)
#define FOR(i,a,b) for(int i = a;i<b;i++)
#define SSTR( x ) static_cast< std::ostringstream & >( \
        ( std::ostringstream() << std::dec << x ) ).str()
#define ALL(s) (s).begin(), (s).end()
using namespace std;
typedef long long unsigned int llu;
typedef long long ll;

int main (){
  string S;
  while (cin >> S){
    int w = 0;
    bool hasStarted = false;
    int cnt = 0;
    REP(i,S.size()){
      if(!hasStarted && S[i] == 'c'){
	hasStarted = true;
	cnt++;
      }

      if(hasStarted){
	cnt++;
	if(S[i] == 'w') w++;
	if(w == 2) break;
      }
    }
    if(w == 2){
      cout << cnt - 1<< endl;
    }else {
      cout << -1 << endl;
    }
  }
  return 0;
}