n = int(input())


ans = [[] for i in range(2 * n - 1)]
for val in reversed(range(2 * n - n + 1, 2 * n)):
    for i in range(val):
        ans[i].append(val)

idx = 0
for val in reversed(range(1, 2 * n - n + 1)):
    rev = -1
    for i in range(val):
        if i < 2:
            ans[idx].append(val)
            idx += 1
        else:
            ans[rev].append(val)
            rev -= 1

print(len(ans))
for res in ans:
    print(*res)