#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    // Return the number of games you can buy

    int count = 0 ;
    int sum = 0 ;


int j = 0 ;;
    int a[100000];
    while ( p > m)
    { a[j] = p;
        p = p -d ;

     j++;

    }
    a[j ] = m ;
    int i  = 0;
    for (;;)
    {
        sum+= a[i];
        if (sum > s)
            break;
        else
        {
            count++;
            if (i != j)
            i++ ;
        }
    }

    return count;
}

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;
}