import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
long n = scanner.nextLong();
long k = scanner.nextLong();
scanner.close();
long result = 0;
long x = 0;
long r = 0;
if (k == n) {
System.out.println(1);
return;
}
if (k == 1) {
x = n / 3;
r = n % 3;
if (r == 0) {
result = 2 * x;
} else {
result = 2 * x + 1;
}
} else{
x = n / (k + 1);
r = n % (k + 1);
if (r == k) {
result = x + 1;
} else {
result = x;
}
}
System.out.println(result);
}
}