n = int(input())
upto = n*2-1
nokorimin = 1
ans = []
for i in range(n-1):
    next = [i for i in range(upto,n*2)]
    ind = nokorimin
    while ind < upto:
        next.append(ind)
        ind += 2
    ans.append(next)
    next = [i for i in range(upto,n*2)]
    ind = nokorimin + 1
    while ind < upto:
        next.append(ind)
        ind += 2
    ans.append(next)
    upto -= 1
    nokorimin += 1

next = [i for i in range(upto,n*2)]
ans.append(next)

print("{}".format(n*2-1))
for j in range(n*2-1):
    L=[str(i) for i in ans[j]]
    L=' '.join(L)
    print(L)