вроде всё правльно
package com.javarush.task.task04.task0419;
/*
Максимум четырех чисел
*/
import java.io.*;
import java.util.*;
public class Solution {
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String name = reader.readLine();
String sge = reader.readLine();
String ge = reader.readLine();
String g = reader.readLine();
int n1 = Integer.parseInt(name);
int n2 = Integer.parseInt(sge);
int n3 = Integer.parseInt(ge);
int n4 = Integer.parseInt(g);//напишите тут ваш код
if (n1>n2&&n1>n3&&n1>n4){
System.out.println(n1);
}if (n2>n1&&n2>n3&&n2>n4){
System.out.println(n2);
}if (n3>n1&&n3>n2&&n3>n4){
System.out.println(n3);
}if (n4>n1&&n4>n3&&n4>n1){
System.out.println(n4);
} if (n1==n2&&n3!=n4&&n1>n3&&n1>n4){
System.out.println(n1);
} if( n1==n3&&n2!=n4&&n1>n2&&n1>n4){
System.out.println(n1);
}if (n1==n4&&n2!=n3&&n1>n2&&n1>n3){
System.out.println(n1);
}if (n2==n3&&n1!=n4&&n2>n1&&n2>n4){
System.out.println(n2);
}if (n2==n4&&n1!=n3&&n2>n1&&n2>n3){
System.out.println(n2);
}if (n3==n4&&n1!=n2&&n3>n1&&n3>n2){
System.out.println(n3);
}if (n1==n2&&n2==n3&&n1!=n4&&n1>n4){
System.out.println(n1);
}if (n1==n2&&n2==n3&&n1!=n4&&n1<n4){
System.out.println(n4);
}if (n1==n2&&n2==n4&&n1!=n3&&n1>n3){
System.out.println(n1);
}if (n1==n2&&n2==n4&&n1!=n3&&n1<n3){
System.out.println(n3);
}if (n1==n3&&n3==n4&&n1!=n2&&n1>n2){
System.out.println(n1);
}if (n1==n3&&n3==n4&&n1!=n2&&n1<n2){
System.out.println(n2);
}if (n2==n3&&n3==n4&&n2!=n1&&n2>n1){
System.out.println(n2);
}if (n2==n3&&n3==n4&&n2!=n1&&n2<n1){
System.out.println(n1);
} if (n1==n2&&n2==n3&&n3==n4){
System.out.println(n1);
}
}
}