I could have misunderstood your question, but here's a program which does as i interpreted your question.
from random import shuffle
numbers = input("Enter your numbers separated by spaces (ex:'1 6 3 1 4')\\> ")
numbers = [int(n) for n in numbers.split(" ")]
final_numbers = numbers[-3:]
shuffle(final_numbers)
final_numbers += numbers[:-3]
print(final_numbers)
(I have not added any kind of negative feedback if the user decides to missuse the program)