#include <iostream>
#include <algorithm>
#include <string>
using namespace std;
int t, cnt;

int main() {
  string s;
  int ans = 101;
  cin >> s;
  for (auto& e : s) {
    if (e == 'c') {
      t = 1;
      cnt = 1;
    } else if (e == 'w') {
      if (t == 1) {
        t++;
        cnt++;
      } else if (t == 2) {
        cnt++;
        t = 0;
        ans = min(ans, cnt);
      }
    } else {
      cnt++;
    }
  }
  if (ans == 101) ans = -1;
  cout << ans << endl;
}