import java.util.*;

public class Main {
    static final int MOD = 1000000007;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int k = sc.nextInt();
        int[] dp = new int[k + 1];
        int max = 0;
        dp[0] = 1;
        for (int i = 2; i <= n; i++) {
            for (int j = max; j >= 0; j--) {
                for (int a = 1; a < i && a + j <= k; a++) {
                    dp[a + j] += dp[j];
                    dp[a + j] %= MOD;
                    max = Math.max(max, a + j);
                }
            }
        }
        int ans = 0;
        for (int x : dp) {
            ans += x;
            ans %= MOD;
        }
        System.out.println(ans);
    }
}