import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String mn = scan.nextLine();
        int m = Integer.valueOf(mn.split(" ")[0].trim()); // 苹果数目
        int n = Integer.valueOf(mn.split(" ")[1].trim()); // 盘子数目
        int[][] dp = new int[n + 1][m + 1];
        for (int i = 0; i <= n; i++) {
            for (int j = 0; j <= m; j++) {
                dp[i][j] = 1;
            }
        }
        for (int i = 2; i <= n; i++) {
            for (int j = 2; j <= m; j++) {
                if (j < i) {
                    dp[i][j] = dp[i - 1][j];
                    continue;
                }
                dp[i][j] = dp[i - 1][j] + dp[i][j - i];
            }
        }
        System.out.println(dp[n][m]);
    }
}