#include <fstream>

using namespace std;
ifstream cin("pascal.in");
ofstream cout("pascal.out");
int r,d,i,j,cnt;
int main()
{
    cin >> r >> d;
    for(i  =0;i < r;i++){
        int c = i,cop = i;
        cop -= (cop - j);
        bool ok = false;
        for(int k = 1;k <= c - j;k++){
           if((i + k) % d == 0 && i + k > j)
               ok = true;
        }
        if(ok)
            cnt++;
    }
    cout << cnt;
    return 0;
}