my code-
#include
using namespace std;
int main ()
{
long long int n,m,x,y,first,last,mid,ans;
cin>>n>>m>>x>>y;
first=1;
last=n;
while(first<=last)
{
mid=(first+last)/2;
if(mid*x<=m+(n-mid)*y)
{
ans=mid;
first=mid+1;
}
else
last=mid-1;
}
cout<<mid;
return 0;
}