当我将变量的声明和分配分开时出现Java错误： expect

public class number{
    public int a;
    a = 300;

    public void print_num(int i){
        System.out.println(i);
    }

    public static void main(String args[]){
        number n1 = new number();
        n1.print_num(n1.a);
    }
}


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 number.java:3: error: <identifier> expected
public class number{
    public int a;
    a =