import java.util.*;

public class arroz {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        long n = s.nextLong();
        long a = s.nextLong();
        long b = s.nextLong();

        long opt1 = n * a;
        long opt2 = (n / 5) * b + (n % 5) * a;
        long opt3 = ((n + 4) / 5) * b;

        long ans = Math.min(opt1, Math.min(opt2, opt3));
        System.out.println(ans);
        s.close();
    }
}