/** An instance contains two Strings */
public class TwoString {
    public String one;
    public String two;
    
    /** Constructor: an instance with (s1, s2) */
    public TwoString(String s1, String s2) {
       one= s1;
       two= s2;
    }
    
    /** = "obj is a non-null TwoString folder whose
     *     fields have the same value as this folder */
    public boolean equals(Object obj) {
        if (obj == null) return false;
        
        TwoString it= (TwoString) obj;
        return this.one == it.one  && this.two == it.two;
    }
    
    
    
}