#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>
using namespace std;

int howManyGames(int p, int d, int m, int s) {
    int cost = p;
    int videoGameCount = 0;
    
    while(s >= m)
    {
        cost = p - videoGameCount * d;

        if(cost <= m)
            cost = m;

        if(s >= cost)
            videoGameCount++;
        s = s - cost;
    }
    return videoGameCount;
}

int main() {
    int p;
    int d;
    int m;
    int s;
    cin >> p >> d >> m >> s;
    int answer = howManyGames(p, d, m, s);
    cout << answer << endl;
    return 0;
}