[split] Python for Everybody 5.2 assignment

[jonchanzw]

largest = None
smallest = None
while True:
    num = input("Enter a number: ")
    if num == "done":
        break
    try:
        fnum = float(num)
    except:
        print("Invalid input")
        continue
    if largest is None :
    	largest = float(num)
    elif num > largest :
        largest = float(num)
    if smallest is None :
        smallest = float(num)
    elif num < smallest :
    	smallest = float(num)
    print(num)
    print("Min:",smallest)
    print("Max:",largest)
print("Maximum is",int(largest))
print("Minimum is",int(smallest))

Can someone help point to where I have gone wrong with the logic please? Thanks!