#include <bits/stdc++.h>

using namespace std;

int main() {

  string S; cin >> S;
  bool ok = 0;
  int cnt = 0, cnter = 0;
  int w = 0;
  for(int i=0; i<S.size(); i++) {
    if(S[i] == 'c') {
      ok = 1;
    }
    if(ok) cnter ++;
    if(ok && S[i] == 'w') {
      cnt ++;
    }
    if(cnt == 2) {
      cout << cnter << endl;
      break;
    }
  }

  cout << -1 << endl;

  return 0;
}