N = int(input())
M = 2*N-1
rem = [(i+1) for i in range(M)]

print(M)
if N == 2:
    print(3, 2)
    print(3, 2)
    print(3, 1)
elif N == 3:
    print(5, 4, 3)
    print(5, 4, 3)
    print(5, 4, 2)
    print(5, 4, 1)
    print(5, 3, 2)
else:
    for l1 in range(N, M):
        for r2 in reversed(range(0, l1+1)):
            if rem[l1] > 0 and rem[r2] > 0:
                r1 = M
                l2 = r2-(N-(M-l1))
                ans = []
                for x in range(l1, r1):
                    rem[x] -= 1
                    ans.append(x+1)
                for x in range(l2, r2):
                    rem[x] -= 1
                    ans.append(x+1)
                print(*ans)