class Solution:
    def merge(self, nums1: 'List[int]', m: int, nums2: 'List[int]', n: int) -> None:
        """
        Do not return anything, modify nums1 in-place instead.
        """
        i,j,k = m-1,n-1,len(nums1)-1
        while i >=0 and j >= 0:
            if nums1[i] >= nums2[j]:
                nums1[k] = nums1[i]
                i -= 1
                k -= 1
            else:
                nums1[k] = nums2[j]
                j -= 1
                k -= 1
        while j >= 0:
            nums1[k] = nums2[j]
            j -= 1
            k -= 1