#include <bits/stdc++.h>
using namespace std;

int dg(int l, int r, int a, int b)
{
    int mid = (l + r) / 2;
    if(mid - b == a)return mid;
    else if(mid - b > a)r = mid - 1;
    else l = mid + 1;
    return dg(l, r, a, b);
}

int main()
{
    int a, b;
    cin >> a >> b;
    cout << dg(INT_MIN, INT_MAX, a, b);
    return 0;
}