#include<iostream>
#include<stdio.h>

using namespace std;

int main(){
    long long int n,a,b,c,g1,d,g2,t,mx;
    cin>>n>>a>>b>>c;
    g1 = n/a;
    g2 = 0;

        d = b-c;
        t = b-d;




    if(g1>=g2) mx = g1;
    else mx = g2;
    cout<<mx<<endl;
}