public class Solution {
    private static final long mod = 1000000007L;
    public int chordCnt(int A) {
        long[] dp = new long[2001];
        Arrays.fill(dp, -1);
        dp[0] = 1;
        dp[2] = 1;
        int ans = (int)(findPossible(dp, 2*A)%(mod));
        return ans;
    }

    private static long findPossible(long[] dp, int p) {
        if(dp[p] != -1) {
            return dp[p];
        }
        long sum = 0;
        for(int i = 1; i <= p - 1; i=i+2) {
            long a1 = findPossible(dp, i-1);
            long a2 = findPossible(dp, p-1-i);
            long possible = a1 * a2;
            sum += possible;
        }
        dp[p] = sum;
        return sum;
    }
}