What is the output of the following program?

public class Main {
    int v;
    static void change(Main m) { m.v = 20; }
    static void replace(Main m) { m = new Main(); m.v = 30; }
    public static void main(String[] args) {
        Main a = new Main();
        change(a);
        replace(a);
        System.out.println(a.v);
    }
}