Что не так?

package com.javarush.task.task04.task0419; /* Максимум четырех чисел */ import com.sun.org.apache.xpath.internal.objects.XNumber; import java.io.BufferedReader; import java.io.InputStreamReader; public class Solution { public static void main(String[] args) throws Exception { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String input1 = reader.readLine(); int a = Integer.parseInt(input1); String input2 = reader.readLine(); int b = Integer.parseInt(input2); String input3 = reader.readLine(); int c = Integer.parseInt(input3); String input4 = reader.readLine(); int d = Integer.parseInt(input4); System.out.println(maximum_of_4_numbers(a,b,c,d)); } public static int maximum_of_4_numbers(int a, int b, int c, int d){ int output; if (maximum_two_numbers(a,b) < maximum_two_numbers(c,d)) output = maximum_two_numbers(c,d); else if (maximum_two_numbers(a,b) > maximum_two_numbers(c,d)) output = maximum_two_numbers(a,b); else output = a; return output; } public static int maximum_two_numbers(int a, int b){ int c; if(a < b) c = b; else if (a > b) c = a; else c = a; return c; } }