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

int main() {
    long long a, b, n, m;
    cin >> a >> b >> n >> m;
    if(a >= b)
        cout << b + (a - b) / (n + 1) << endl;
    else
        cout << a + (b - a) / (m + 1) << endl;
}