Exercize to understand from three numbers which is more high

[^Bart]

> In my experience based on decades of writing programs...
> 
> 1. The assignment/exercise/problem should be a write a function with a 
> particular signature.  So first decide on the signature.
> 
> def max3(n1, n2, n3):
>      "Return the max of the three inputs."
>      return None  # To be replaced.

I need to do this exercize just by using if, elif and else, in the next 
lesson we'll discuss other kind of rules! :)

So I need to insert three int numbers and I should show which is the 
high, the middle and the min.

# Exercize 305

number1 = int( input("Insert the first number: "))

number2 = int( input("Insert the second number: "))

number3 = int( input("Insert the third number: "))

numbermax = number1

numbermiddle = number2

numbermin = number3

if number2 > number1 and number2 > number3:
     numbermax = number2

if number3 < number2 and number3 < number1:
     numbermin = number3

else:
     numbermiddle is number1

print("Number max is: ",numbermax, "Number middle is; 
",numbermiddle,"Number min is: ", numbermin)

if number2 < number1 and number2 < number3:
     numbermin = number2

if number3 > number2 and number3 > number1:
     numbermax = number3

else:
     numbermiddle is number2

print("Number min is: ",numbermin)

I don't understand how could I fix it :\