c=n=int(input())
s=range(1,n*n+1)
l=[i for i in s]
d=[1,n,-1,-n]*n
p=1
m=q=n-1
while m:
 for i in [0]*m:q+=d[p];c+=1;l[q]=c
 p+=1
 if p%2:m-=1
for i in s:print(("%03d"+"\n "[i%n!=0])%l[i-1],end="")