#include <iostream>
#include <vector>
#include <list>
#include <algorithm>
#include <string>
#include <sstream>
#include <stack>
#include <iomanip>
#include <numeric>
#include <queue>
#include <climits>
#include <set>
#include <complex>
#include <cmath>
#include <cstring>
#include <map>
using namespace std;
using ll = long long;
#define MOD 1000000007
#define INF 1LL << 59
using ld = long double;

int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    //cout << fixed << setprecision(5);
    int A, B, C, D;
    cin >> A >> B >> C >> D;

    int t = A + B;

    for (int i = 0; i <= t; ++i)
    {
        if (i + C * i > D)
        {
            cout << i - 1 << endl;
            return 0;
        }
    }
    cout << t << endl;
    return 0;
}