Giúp em với huhuhuuhuhhuu

`color(#FFFFFFff)(H)color(#E7E7E7ff)(o)color(#CFCFCFff)(r)color(#B7B7B7ff)(i)color(#9F9F9Fff)(z)color(#878787ff)(o)color(#6F6F6Fff)(n)`

#include <bits/stdc++.h>
using namespace std;

int main() {
    int n, m, a, b;
    cin >> n >> m >> a >> b;
    cout << min(n*a,(n/m)*b+min((n%m)*a,b));
}

//khanhtaon
#include <iostream>
using namespace std;
int n, m, a, b;
int main()
{
    cin >> n >> m >> a >> b;
    cout << min(n*a,(n/m)*b + min((n%m)*a, b));
}