What am I doing wrong? I can't see any issue with the code

package com.codegym.task.task02.task0204; /* Family relations */ public class Solution { public static void main(String[] args) { //write your code here Man man = new Man(); Woman woman = new Woman(); woman.husband=Man; Man.wife=Woman; } public static class Man { public int age; public int height; public Woman wife; } public static class Woman { public int age; public int height; public Man husband; } }