#include <bits/stdc++.h>
#define REP(i,n) for(int i=0;i<n;i++)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define SSTR( x ) static_cast< std::ostringstream & >( \
        ( std::ostringstream() << std::dec << x ) ).str()
#define ALL(s) (s).begin(), (s).end()
using namespace std;
typedef long long unsigned int llu;
typedef long long ll;


int main (){
  string S;
  while (cin >> S){
    int w0 = -1;
    int w1 = -1;
    int ans = INT_MAX;
    bool b = false;
    
    REP(i,S.size()){
      if(S[i] == 'c'){
	w0 = i;
      }
      if(S[i] == 'w'){
	if(w0 == -1) continue;
	if(w1 != -1){
	  ans = min(ans, i - w1 + 1);
	  b = true;
	}
        w1 = w0; 
      }
    }
    if(b) cout << ans << endl;
    else cout << -1 << endl;
  }

  return 0;
}