#include <bits/stdc++.h>
using namespace std;

int main() {
  string s; cin >> s;
  int ans = 101101;
  int n = s.size();
  int w1 = n, w2 = n;
  for (int i = n - 1; i >= 0; i--) {
    if (s[i] == 'w') {
      w1 = w2;
      w2 = i;
    }
    if (s[i] == 'c' && w1 != n) {
      ans = min(ans, w1 - i + 1);
    }
  }
  if (ans == 101101) cout << -1 << endl;
  else cout << ans << endl;
  return 0;
}