How do I solve this below question

# Reading the input
import ast 
input_lists = ast.literal_eval(input())
m = input_lists[0]
n = input_lists[1]
def union_array(arr1, arr2):
    m = len(arr1)
    n = len(arr2)
    i = 0
    j = 0
     
    # keep track of last element to avoid duplicates
    prev = None
     
    while i < m and j < n:
        if arr1[i] < arr2[j]:
            if arr1[i] != prev:
                print(arr1[i], end=' ')
                prev = arr1[i]
            i += 1
        elif arr1[i] > arr2[j]:
            if arr2[j] != prev:
                print(arr2[j], end=' ')
                prev = arr2[j]
            j += 1
        else:
            if arr1[i] != prev:
                print(arr1[i], end=' ')
                prev = arr1[i]
            i += 1
            j += 1
             
    while i < m:
        if arr1[i] != prev:
            print(arr1[i], end=' ')
            prev = arr1[i]
        i += 1
 
    while j < n:
        if arr2[j] != prev:
            print(arr2[j], end=' ')
            prev = arr2[j]
        j += 1