#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;

ll A, B, N, M;

int main() {
  cin >> A >> B >> N >> M;
  if (A <= B) cout << A + (B - A) / (M + 1) << endl;
  else cout << B + (A - B) / (N + 1) << endl;
  return 0;
}