#include
using namespace std;
int main(){
long long m=0,scholarship=0,mid=0,n=0,x=0,y=0;
cin>>n>>m>>x>>y;
while(m>=x){
m=m-x;
scholarship++;
if(scholarship==n){
cout<<n;
exit(0);
}
}
mid=n-scholarship;
m=m+y*mid;
while(m>=x){
m=m-x;
scholarship++;
if(scholarship==n){
cout<<n;
exit(0);
}
}
cout<<scholarship;
}