package yuki172;

import java.util.Scanner;

public class C {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int M = sc.nextInt();
		int N = sc.nextInt();
		sc.close();
		System.out.println(M+((double)N)/3);
	}

}