mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    N = int(input())

    print(2 * N - 1)
    ans = [[] for _ in range(2 * N - 1)]
    for i in range(2 * N - 1, N, -1):
        for j in range(i):
            ans[j].append(i)
    cnt = 0
    for i in range(N, 1, -1):
        ans[cnt].append(i)
        ans[cnt + 1].append(i)
        cnt += 2
        for j in range(i - 2):
            ans[-j - 1].append(i)
    ans[-1].append(1)
    for line in ans:
        print(*line)


if __name__ == '__main__':
    main()