import java.util.*;
class mymath
{ long a; long b;

long add(){System.out.println("instance");return a+b;}
long sub(){System.out.println("instance");return a-b;}
long mul(){System.out.println("instance");return a*b;}
long div(){System.out.println("instance");return a/b;}  


static long add(long a, long b){return a+b;}
static long sub(long a, long b){return a-b;}
static long mul(long a, long b){return a*b;}
static long div(long a, long b){return a/b;}
}


public class static_method {
	public static void main(String[] args)
	{
		System.out.println(mymath.add(20L, 30L));
	}

}