Python minority output program question. Help me

There are three ways to format strings in Python.

I prefer the fast string, so I modified it in that way.

a = int(input('number input :'))
b = 0

for i in range(2, a):
    if a % i == 0:
        b = 1

if b == 0:
    print(f"{a} is a decimal.)
else:
    print(f"{a} is not a decimal.)

Write f in front of the quotation mark of the print inquiry as above

{variable name} where the variable in quotation marks will be outputYou can write it down like .

If you search the other two methods on Google, you can find them well, so please refer to them.

* When you upload the code, type it in text and wrap the beginning and end with `` and ``, and it goes up nicely. If you post it as a picture, it may be difficult to get an answer because you have to type it yourself.

* The method of finding the decimal point of the source works properly. However, it can take a long time if a large number goes in. I think it would be good to refer to Eratosthenes' sieve .