// Created at 2021/03/31 14:00
// {TODO}WA, {TODO}min, {TODO}diff
// goal: {TODO}min
#include <bits/stdc++.h>
//#include <atcoder/all>
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define overload4(_1,_2,_3,_4,name,...) name
#define rep(i, n) for (lint i = 0, i##_lim = n; i < i##_lim; i++)
#define rep2(i, n) for (lint i = 1, i##_lim = n; i <= i##_lim; i++)
#define rep3(i, s, e) for (lint i = s, i##_lim = e; i < i##_lim; i++)
#define all(i) (i).begin(), (i).end()
#define print1(s) cout << (s) << '\n';
#define print2(s1, s2) cout << (s1) << ' ' << (s2) << '\n';
#define print3(s1, s2, s3) cout << (s1) << ' ' << (s2) << ' ' << (s3) << '\n';
#define print4(s1, s2, s3, s4) cout << (s1) << ' ' << (s2) << ' ' << (s3) << ' ' << (s4) << '\n';
#define print(...) overload4(__VA_ARGS__, print4, print3, print2, print1)(__VA_ARGS__)
using namespace std;
//using namespace atcoder;
using lint = long long;
using ld = long double;
using pi = pair<int, int>;
using pl = pair<lint, lint>;
using vi = vector<int>;
using vl = vector<lint>;
using vvi = vector<vi>;
using vvl = vector<vl>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using qi = queue<int>;
using ql = queue<lint>;
using qpi = queue<pi>;
constexpr int INF = 1 << 30;
constexpr lint INFl = 1LL << 62;

template<class T, class U>
istream &operator>>(istream &is, pair<T, U> &pair) {
    is >> pair.first >> pair.second;
    return is;
}

template<class T, class U>
ostream &operator<<(ostream &os, pair <T, U> &pair) {
    os << pair.first << ' ' << pair.second;
    return os;
}

template<class T>
istream &operator>>(istream &is, vector<T> &vec) {
    for (auto &v : vec) is >> v;
    return is;
}

template<class T>
ostream &operator<<(ostream &os, const vector<T> &vec) {
    os << '[';
    for (auto v : vec) os << v << ", ";
    os << ']';
    return os;
}

template<class T>
inline bool chmax(T &a, T b) {
    if (b > a) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
inline bool chmin(T &a, T b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
//    cout << fixed << setprecision(15);
    // 二分探索
    // 全探索
    // 動的計画法
    // 逆からたどる
    // ネットワークフロー
    // 二部マッチング
    // ggrks
    /*----------------------------------------------------*/
    lint a, b, n, m; cin >> a >> b >> n >> m;
    if (a > b) {
        print(b + (a - b) / (n + 1))
    } else {
        print(a + (b - a) / (m + 1))
    }

    // 最大値は?
}