#! /usr/bin/env python3

def Reverse(arr, head, end):
	while head < end:
		arr[head], arr[end] = arr[end], arr[head]
		head += 1
		end -= 1

def ReverseSentence(arr):
	arr_len = len(arr)
	if arr_len == 0:
		return arr

	head = 0
	end = arr_len - 1
	Reverse(arr, head, end)

	