I tested the program with N values equal 0 and negative numbers and it doesn't display anything. I don't understand why the program is failing the last requirement.

package com.codegym.task.task05.task0532;
import java.io.*;
/*
Task about algorithms
*/
public class Solution {
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
int N = Integer.parseInt(reader.readLine());
int maximum = Integer.parseInt(reader.readLine());
if (N > 0){
int number = 0;
for (int i = 0; i < N - 1; i++){
number = Integer.parseInt(reader.readLine());
if (number > maximum){
maximum = number;
}
}
System.out.println(maximum);
}
}
}