Please do not use special functions. (Python)

Write a program that inputs positive integer value from the user. The program should find and display the second largest digit in the input number. Note: the number of digits may vary. Sample Run: Enter positive integer (negative to quit): 1429 The second largest digit in 1429 is 4 Sample Run: Enter positive integer (negative to quit): 1234 The second largest digit in 1234 is 3 Sample Run: Enter positive integer (negative to quit): -25 Number cannot be Negative Sample Run: Enter positive integer (negative to quit): 5 Number must be at least two-digits