import java.util.Scanner; public class Main { public int howManyTrees(int n) { if (n < 1) return 0; else if (n == 1) return 1; else if (n == 2) return 2; else { int mod = (int) 1e9 + 7; long[] num = new long[n + 1]; num[0] = 1; num[1] = 1; for (int i = 2; i < n + 1; i++) { num[i] = 0; for (int j = 0; j < i; j++) { num[i] = num[i] + (num[j] * num[i - 1 - j]) % mod; num[i] %= mod; } } return (int)num[n]; } } public static void main(String[] args) { Main main = new Main(); Scanner scanner = new Scanner(System.in); int n = scanner.nextInt(); System.out.println(main.howManyTrees(n)); } }