n = int(input())
m = 2 * n - 1
ans = [[] for _ in range(m)]
l = 1
r = m + 1
while l < r:
    cnt = r - l
    if cnt == 1:
        ans[0].append(l)
        break
    mx = r - 1
    for i in range(cnt):
        ans[i].append(mx)
    nxt = l + 2
    ans[cnt - 1].append(l)
    for i in range(cnt // 2 - 1):
        ans[cnt - 1].append(l + 2 + i)
    ans[cnt - 2].append(l + 1)
    for i in range(cnt // 2 - 1):
        ans[cnt - 2].append(l + 2 + cnt // 2 - 1 + i)
    l += 1
    r -= 1
print(m)
for a in ans:
    print(*a)