1314 : 문자사각형2

n = int(input())

arr = [[0 for i in range(n+1)] for j in range(n+1)]
alph=ord('A')

for i in range(n):
    if i %2==0:
        for j in range(n):
            arr[j][i]=alph
            alph+=1
            if alph > ord('Z'):
                alph = ord('A')
    else :
        for j in range(n):
            arr[n-1-j][i]=alph
            alph+=1
            if alph > ord('Z'):
                alph = ord('A')

for i in range(n):
    for j in range(n):
        print(chr(arr[i][j]),end=' ')
    print()