#include <iostream>
#include <string>
#include <queue>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  string s;
  queue<int> q;
  cin >> s;
  int ret = 101;
  for( int i = s.size()-1; i>=0; i-- ){
    if( s[i] == 'w' ){
      q.push( i );
      if( q.size() > 2 ) q.pop();
    }
    if( s[i] == 'c' && q.size() == 2 ){
      ret = min( ret, q.front() - i + 1 );
    }
  }
  if( ret > 100 ) cout << -1 << endl;
  else cout << ret << endl;
}