#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> llp;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ii> vii;
typedef vector<vii> vvii;
#define pb(x) push_back(x)
#define mp(x, y) make_pair(x, y)

int main(int argc, char **argv) {

	//freopen("input", "r", stdin);
	//freopen("output", "w", stdout);

	ios_base::sync_with_stdio(0);
	cin.tie(0);

	int p, d, m, s; cin >> p >> d >> m >> s;
	int cost = p + d;
	int cnt = 0;
	while (s) {
		if (cost > m) cost -= d;
        if (cost < m) cost = m;
		if (cost <= s) {
			s -= cost;
			cnt++;
		}
		else break;
	}
	cout << cnt << endl;

	return 0;
}