import java.util.*;
import java.io.*;

/**
 * This is a version of the String class, which
 * uses an array of chars to represent a string.
 */
public class OurString {

  /** An array of characters representing a string.*/
  private char[] string; 

  /**
   * Create a string (using array of characters).
   */
  public OurString(char[] s) {
    
  }

  /** 
   * Return the length of the string of characters.
   */
  public int length() {
    return 0;
  }

  /**
   * Return the character at the given index i.
   */
  public char charAt(int i) {
    return 0;
  }

  /** 
   * Return the substring from index i up to index j.
   */
  public char[] substring(int i, int j) {
    return null;
  }
  
  /** 
   * Return the index of the first occurence of the specified 
   * character, and if the character does not exist in the array
   * then return -1.
   */
  public int indexOf(char c) {
    return 0;
  }
}