//英雄(笑)装備
#include<iostream>
#include<algorithm>
#include<queue>
#include<stack>
#include<string.h>
#include<vector>
#include<stdio.h>
using namespace std;
int main() {
	int a, b, c;
	scanf("%d%d", &a, &b);
	c = a + b ;
	c = c / 2;
	printf("%d\n", c);
	return 0;
}
