#include <iostream>
#include <list>
#include <vector>
#include <string>
#include <stdio.h>
#include <stdint.h>
using namespace std;

using uint = unsigned int;
using ll = long long;

#define CIN( LL , A ) LL A; cin >> A 
#define GETLINE( A ) string A; getline( cin , A ) 


int main()
{

  CIN( string , S );
  const uint& size = S.size();
  const string c = "c";
  const string w = "w";
  ll min_num = -1;
  ll cww1 = -1;
  ll cww2 = -1;
  

  for( ll i = 0 ; i < size ; i++ ){

    const string s = S.substr( i , 1 );

    if( s == c ){

      cww2 = i;

    } else if( s == w ){

      if( cww1 != -1 ){
	  
	const ll d = i - cww1 + 1;

	if( min_num == -1 || d < min_num ){

	  min_num = d;

	}

      }

      if( cww2 != -1 ){

	cww1 = cww2;
	cww2 = -1;

      }

    }

  }
  
  cout << min_num << endl;
  return 0;

}