// Immutable class -- cannot be changed
import java.util.*;
public class Str2 {
    private List<Character> data;
    public Str2() { data = new ArrayList<Character>(); }
    public Str2(char[] in) {
        data = new ArrayList<Character>();
        for(int i=0;i<in.length;i++)
            data.add(in[i]); }
    public Str2(Str2 s) {
        data = s.data; }
    public String toString() {
        StringBuilder sb = new StringBuilder();
        for(Character c : data)
            sb.append(c);
        return sb.toString();
    }
    public boolean equals(Object o) {
        if(o instanceof Str2) {
            Str2 that = (Str2)o;
            //return this.toString().equals(that.toString());
            if(this.length() != that.length()) return false;
            for(int i=0;i<this.length();i++)
                if(this.get(i).equals(that.get(i))) return false;
            return true;
        }
    }
    public char charAt(int n) { return data.get(n); }
    public int length() { return data.size(); }
    
    public static void main(String[] args) {
        Str2 s2 = new Str2(new char[]{'h','e','l','l','o'});
        System.out.println(s2);
    }
}