Syntax error for declaration of user defined objects

class add{
    // private int q;
    // private int z;
    public add(){
        this.s=0;
        this.f=0;
    }
    public int a(int g,int d){
        this.s = g;
        this.f = d;

        return g+d;
    }
    public void main(String[] args) {
        add d = new add();		
    }

}