//template by chamow
#include<bits/stdc++.h>
/*-------------------------------------------------------- */
using namespace std;

/*-------------------------------------------------------- */

#define rep(i,val,n) for(ll i=val;i<n;i++)
#define per(j,val,n) for(ll j=val;j>=n;j--)
#define pb push_back
#define pi 3.14157
#define mp make_pair
#define MODULO 1000000007
#define INF 1000000000000000
#define fastread ios_base::sync_with_stdio(false); cin.tie(NULL);


/*-------------------------------------------------------- */

typedef long long ll;
typedef vector<bool> boolean;
typedef vector<ll> vec;


/*-------------------------------------------------------- */

ll gcd(ll a, ll b)
{
	if(b == 0)
	{
		return a;
	}
	return gcd(b, a%b);
}

ll lcm(ll a, ll b)
{
	return ((a*b)/gcd(a,b));
}

/*-------------------------------------------------------- */

int main()
{
	fastread;
	ll p, d, m, s;
	ll counter = 0;
	cin>>p>>d>>m>>s;
	while(s > 0)
	{
		ll rem = 0;
		if(p <= m)
		{
			if((s-m) >= 0)
				s -= m;
			else
				break;
		}
		else
		{
			if((s-p) >= 0)
			s -= p;
		else
			break;
		}
		p -= d;
		++counter;


	}
	cout<<counter;
	return 0;
}