c=n=int(input()) r=range a=n*n l=[i for i in r(1,a+1)] d=[1,n,-1,-n]*99 p=1 m=q=n-1 while m: for i in r(m):q+=d[p];c+=1;l[q]=c p+=1 if p%2==1:m-=1 for i in r(1,a+1):print(("%03d"+["\n"," "][i%n!=0])%l[i-1],end="")