import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        double a = scan.nextDouble();
        double b = scan.nextDouble();
        
        double multiplier = a / 2 + b / 2;
        int answer = (int) multiplier;
        System.out.println(answer);
    }
}