import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int D = sc.nextInt();

		if (N <= D) {
			System.out.println(1);
			return;
		}

		int count = 1, idx = D + 1;
		while (idx < N) {
			idx += D + 1;
			if(idx <= N) count++;
			idx += D;
		}
		System.out.println(count);
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int D = sc.nextInt();

		if (N <= D) {
			System.out.println(1);
			return;
		}

		int count = 1, idx = D + 1;
		while (idx < N) {
			idx += D + 1;
			if(idx <= N) count++;
			idx += D;
		}
		System.out.println(count);
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int D = sc.nextInt();

		if (N <= D) {
			System.out.println(1);
			return;
		}

		int count = 1, idx = D + 1;
		while (idx < N) {
			idx += D + 1;
			if(idx <= N) count++;
			idx += D;
		}
		System.out.println(count);
	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int D = sc.nextInt();

		if (N <= D) {
			System.out.println(1);
			return;
		}

		int count = 1, idx = D + 1;
		while (idx < N) {
			idx += D + 1;
			if(idx <= N) count++;
			idx += D;
		}
		System.out.println(count);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int D = sc.nextInt(); D sc.nextInt() sc.nextInt sc if (N <= D) {
			System.out.println(1);
			return;
		} N <= D N D {
			System.out.println(1);
			return;
		} System.out.println(1) System.out.println System.out System System.out 1 return; int count = 1 count 1 idx = D + 1; idx D + 1 D 1 while (idx < N) {
			idx += D + 1;
			if(idx <= N) count++;
			idx += D;
		} idx < N idx N {
			idx += D + 1;
			if(idx <= N) count++;
			idx += D;
		} idx += D + 1 idx D + 1 D 1 if(idx <= N) count++; idx <= N idx N count++ count idx += D idx D System.out.println(count) System.out.println System.out System System.out count String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int D = sc.nextInt();

		if (N <= D) {
			System.out.println(1);
			return;
		}

		int count = 1, idx = D + 1;
		while (idx < N) {
			idx += D + 1;
			if(idx <= N) count++;
			idx += D;
		}
		System.out.println(count);
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int D = sc.nextInt();

		if (N <= D) {
			System.out.println(1);
			return;
		}

		int count = 1, idx = D + 1;
		while (idx < N) {
			idx += D + 1;
			if(idx <= N) count++;
			idx += D;
		}
		System.out.println(count);
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int D = sc.nextInt();

		if (N <= D) {
			System.out.println(1);
			return;
		}

		int count = 1, idx = D + 1;
		while (idx < N) {
			idx += D + 1;
			if(idx <= N) count++;
			idx += D;
		}
		System.out.println(count);
	}

}