Code is returning the incorrect values. syntax error

[007sonic]

Just trying to figure out why my code here is returning the incorrect minimum and maximum values. tried flipping the ">" and "<" around and it still doesn't work. I'm not meant to use the min() and max() functions here. My thought was maybe I should hold all of the input values in another variable and then check that one for the min and max values?

largest = None
smallest = None
while True:
    num = input("Enter a number: ")
    if num == "done":
        break
    try:
        int(num)
    except:
        print('Invalid input')
        continue
    if largest is None :
        largest = num
    elif num < largest :
        largest = num
    if smallest is None :
        smallest = num
    elif num > smallest :
        smallest = num
    # print(num)

print("Maximum is", largest, "Minimum is", smallest)

Output:
Enter a number: 9
Enter a number: 41
Enter a number: 12
Enter a number: 3
Enter a number: 74
Enter a number: 15
Enter a number: done
Maximum is 12 Minimum is 9