#include "iostream"

using namespace std;
int main()
{
    int a, b, rz;
    cin >> a >> b;
    if (b == 2 && a != 1 || b == 1 && a != 1) {
        rz = 2 * a / b;
    }
    else {
        if (a % b != 0) {
            rz = 2 * (a / b + 1);
        }
        else {
            rz = 2 * a / b;
        }
    }
    cout << rz;
    return 0;
}

i tested it a lot, pleas help may be i am so silly....