n = int(input()) a = 0 for i in range(1 << 2 * n): if not i & 1: continue if i >> 2 * n & 1: continue if bin(i).count("1") != n: continue s = 0 for j in range(2 * n): if i >> j & 1: s += 1 else: s -= 1 if s < 0: break if s == 0: a += 1 print(a)