import java.util.*;
public class Test11 {
  public static void main(String[] args){
    Scanner sc=new Scanner(System.in);
    String line;
    line=sc.nextLine();
    int n=line.length();
    ArrayList<Integer> c_=new ArrayList<>(),w_=new ArrayList<>();
    for(int i=0;i<n;i++){
      switch(line.charAt(i)){
      case 'c':
        c_.add(i);
        break;
      case 'w':
        w_.add(i);
        break;
      }
    }
    int min=Integer.MAX_VALUE;
    for(int i=0;i<c_.size();i++){
      int tmp=c_.get(i),tmp1=Integer.MAX_VALUE;
      int i1;
      for(i1=1;i1<w_.size();i1++){
        int tmp2=w_.get(i1-1);
        if(tmp<tmp2){
          tmp1=w_.get(i1)-tmp+1;
          break;
        }
      }
      if(tmp1<min) min=tmp1;
      if(i1==w_.size()) break;
    }
    if(min==Integer.MAX_VALUE) min=-1;
    System.out.println(min);
    sc.close();
  }
}