#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    ll A,B,N,M; cin >> A >> B >> N >> M;
    if(A <= B)
        cout << A + (B - A) / (M + 1) << endl;
    else
        cout << B + (A - B) / (N + 1) << endl;
}