#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208;

int main() {
    ll a, b, n, m;
    cin >> a >> b >> n >> m;
    if(a < b) cout << a + (b-a)/(m+1) << "\n";
    else cout << b + (a-b)/(n+1) << "\n";
    return 0;
}