import sys
input = sys.stdin.readline
from collections import Counter

N=int(input())

ANS=[[0]*N for i in range(2*N-1)]

r=0
c=0

for i in range(1,2*N):
    for j in range(i):
        ANS[r][c]=i
        r+=1

        if r==2*N-1:
            r=0
            c+=1



C=Counter()
for x in ANS:
    C[tuple(x)]+=1

ANS=[]

for x in C:
    if C[x]==1:
        ANS.append(x)
    else:
        ANS.append(x)
        ANS.append(x)

print(len(ANS))

for x in ANS:
    print(*x)