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

signed main(){
  string S;
  cin >> S;
  
  bool fg1 = false;
  bool fg2 = false;
  int cnt = 0;
  int ans = 10000000;
  for( int i = 0; i < S.size(); i++ ){
    cnt++;
    if( S.at(i) == 'c' ){
      if( fg2 == false ){
        fg1 = true;
        cnt = 1;
      }
    }else if( S.at(i) == 'w' ){
      if( fg2 ){
        ans = min(ans, cnt);
        fg1 = false;
        fg2 = false;
      }else if( fg1 == true && fg2 == false ){
        fg2 = true;
      }
    }
  }
  
  if( ans != 10000000 ) cout << ans << endl;
  else cout << -1 << endl;
}