3007

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    ifstream fin("input.txt");
    ofstream fout("output.txt");

    int n, k;
    fin >> n >> k;
    vector<vector<vector<long long>>> dp(2 * n + 1, vector<vector<long long>>(2 * n + 1, vector<long long>(2*n + 1)));
    dp[0][0][0] = 1;
    for (int i = 0; i < 2 * n; i++)
        for (int j = 0; j <= i; j++)
            for (int g = 0; g <= i; g++) {
                dp[i + 1][j + 1][max(g, j + 1)] += dp[i][j][g];
                dp[i + 1][j + 1][max(g, j + 1)] %= 1000 * 1000 * 1000 + 7;
                if (j > 0) {
                    dp[i + 1][j - 1][g] += dp[i][j][g];
                    dp[i + 1][j - 1][max(g, j + 1)] %= 1000 * 1000 * 1000 + 7;
                }
            }
    fout << dp[2 * n][0][k] << endl;

    fin.close();
    fout.close();
    return 0;
}