import java.util.*;

public class Exercise31{
  public static void main (String[] args){

    Scanner sc = new Scanner(System.in);

    String str = sc.next();
    char[] charArray = str.toCharArray();

    int min = charArray.length;
    boolean flag = false;

    for (int a = 0; a < charArray.length; a++){
      if (charArray[a] == 'c'){
        int w = 0;
        forW: for (int b = a + 1; b < charArray.length; b++){
          if (charArray[b] == 'w'){
            w++;
          }
          if (w == 2){
            flag = true;
            min = Math.min(min, (b + 1) - a);
            break forW;
          }
        }
      }
    }

    if (flag){
      System.out.println(min);
    }else{
      System.out.println(-1);
    }
  }
}