Змейка

n = int(input())
a = [[0 for j in range(n)] for i in range(n)]
cur = 1
nap = 0
for i in range(n):
    if nap == 0:
        x = 0
        y = i
        while x <= i and y >= 0:
            a[x][y] = cur
            cur += 1
            x += 1
            y -= 1
        nap = 1
    else:
        x = i
        y = 0
        while x >= 0 and y <= i:
            a[x][y] = cur
            cur += 1
            x -= 1
            y += 1
        nap = 0
for j in range(1, n):
    if nap == 0:
        x = j
        y = n - 1
        while x <= n - 1 and y >= j:
            a[x][y] = cur
            cur += 1
            x += 1
            y -= 1
        nap = 1
    else:
        x = n - 1
        y = j
        while x >= j and y <= n - 1:
            a[x][y] = cur
            cur += 1
            x -= 1
            y += 1
        nap = 0
for i in range(n):
    print(*a[i], sep='\t')