list(zip(*arr[::-1]))

import sys
sys.setrecursionlimit(10**6)

from operator import mul
from functools import reduce

def nCr(n, r):
    r = min(r, n-r)
    numer = reduce(mul, range(n, n-r, -1), 1)
    denomi = reduce(mul, range(1, r+1), 1)
    return numer // denomi