n = int(input())

print(2 * n - 1)
for i in range(2 * n - 1):
    ANS = []
    if i < n + 1:
        for j in range(n - 1):
            ANS.append(2 * n - 1 - j)
        if i == n:
            ANS.append(i)
        else:
            ANS.append(i + 1)
    else:
        for j in range(2 * n - i - 1):
            ANS.append(2 * n - 1 - j)
        for j in range(i - n + 1):
            ANS.append(n - j)
    print(*ANS)