#include <iostream>
#include <algorithm>
using namespace std;

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