Get the maximum even sum of the K Elements

max_sum_k.py

def get_max_even_sum (input_arr, k):
    if k > len(input_arr) or len(input_arr) == 0:
        return -1

    even_arr = []
    odd_arr = []
    # sort the arr
    input_arr.sort(reverse = True)
    
    # separate out the even and odd arr
    for i in range(len(input_arr)):
        if input_arr[i]%2 == 0:
            even_arr.append(input_arr[i])
        else:
            odd_arr.append(input_arr[i])
    
    # take the max and keep track of the remaining
    even_index, odd_index = 0, 0
    max_sum = 0
    
    # Go Greedy
    # think about the case with only 1 or 2 element
    # for 1:
        # we must take the highest from the even Array
        # for 2: we can either take (even + even = even) or (odd + odd = even) 
            # since even + odd is not equal to even
            # we take max(current + next number) from even and odd array

    while k > 0:
        if k % 2 == 1:
            if (len(even_arr) > 0):
                max_sum += even_arr[even_index]
                even_index += 1
                k -= 1
            else:
                return -1
        else:
            if even_index < len(even_arr) - 1 and odd_index < len(odd_arr) - 1:
                max_sum += max(even_arr[even_index] + even_arr[even_index + 1], odd_arr[odd_index] + odd_arr[odd_index + 1])
                even_index += 2
                odd_index += 2
            elif even_index < len(even_arr) - 1:
                max_sum += even_arr[even_index] + even_arr[even_index + 1]
                even_index += 2
            elif odd_index < len(odd_arr) - 1:
                max_sum += odd_arr[odd_index] + odd_arr[odd_index + 1]
                odd_index += 2
            
            k -= 2

    return max_sum        
    
# Try these sample I/O:
# print(get_max_even_sum([4,2,6,7,8], 3))
# print(get_max_even_sum([1,1,1], 3))
# print(get_max_even_sum([1,1], 3))
# print(get_max_even_sum([1], 3))
# print(get_max_even_sum([1], 3))
# print(get_max_even_sum([], 0))
# print(get_max_even_sum([1,2], 1))
# print(get_max_even_sum([1,2], 2))
# print(get_max_even_sum([ 2, 4, 10, 3, 5 ], 3))
# print(get_max_even_sum([ 5,5,1,1,3 ], 3))
# print(get_max_even_sum([4,2,6,7,8], 3))
# print(get_max_even_sum([5, 5, 2, 4, 3], 3))
# print(get_max_even_sum([-1,-2,-2], 3))
# print(get_max_even_sum([1,2,4,11], 100))
# print(get_max_even_sum([1,2,4,11], 1))
# print(get_max_even_sum([5, 5, 1, 1, 3], 3))
    

For this Example test: ([5, 6, 3, 4, 2], 5) it gives incorrect output: 14 whereas it should be 20... What can be corrected?