#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  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;
  return 0;
}