func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, m, a, b, t, u;     cin >> n >> m >> a >> b;     if (a <= (float(b) / float(m))) {       cout << n * a;     } else {       t = ceil(float(n) / float(m)) * b;       u = n / m * b + n % m * a;       cout << min(t, u);     }   }   