Hello, @pritamrajak, and welcome to Python Software Foundation Discourse!
Please copy, paste, and format your code for posting, rather than post a picture or captured image of it.
You can use fences of three backticks before and after code to format it, as follows:
```
print("Hello, world!")
```
The following links provide information about that, along with other useful information:
The following is something to thing about, regarding your post:
>>> int("065")
65
After "065" is converted to an int, the leading 0 is not needed to represent the value of the number, and that’s why it is not there.
EDIT:
Let’s clarify this still further. Regarding your code, after the conversion to int, the value of rev is just 65. The fact that there was a leading "0" in s prior to the conversion becomes irrelevant.