#include <bits/stdc++.h>

using namespace std;
const int INF = 10000000;
typedef long long ll;

int main() {
  string s;
  cin >> s;
  vector<int> c;
  vector<int> w;
  for (int i = 0; i < s.size(); ++i) {
    if (s[i] == 'c') c.push_back(i);
    if (s[i] == 'w') w.push_back(i);
  }

  int ans = INF;
  for (int i = 0; i < c.size(); ++i) {
    int cnt = 0;
    for (int j = 0; j < w.size(); ++j) {
      if (w[j] > c[i]) {
	cnt++;
	if (cnt == 2) {
	  ans = min(ans, w[j] - c[i] + 1);
	}
      }
    }
  }
  if (ans == INF) puts("-1");
  else cout << ans << '\n';
  return 0;
}