arr = [1,2,3,4,5,6]

for i in range(len(arr)-1-1-1):
    if arr[i] % 2 != 0:
        arr.remove(arr[i])

while len(arr) > 1:
    arr.remove(arr[0])
    arr.append(arr[0])
    arr.remove(arr[0])

print(arr)