n = int(input())
print(2 * n - 1)
lst = [[] for _ in range(n)]

for i in range(n - 1):
    i1 = i + 1
    i2 = 2 * n - 1 - i1
    if i % 2 == 0:
        i1, i2 = i2, i1
    for _ in range(i1):
        lst[i].append(i1)
    for _ in range(i2):
        lst[i].append(i2)
    
lst[-1] = [2 * n - 1] * (2 * n - 1)

for row in zip(*lst):
    print(*row)