why is this not read correctly by the compiler?

for task "display the square of a number" i run

public class Solution {
    public static int number = 25;

    public static void main(String[] args) {
        int a = 5;
        int b = a * a ;
        System.out.println(b);
    }
};

and it says that it is not a square... what is wrong here the task in question is https://codegym.cc/tasks/com.codegym.task.task01.task0140