Example:

`num_1 = 1010`

`num_2 = 1234`

`num_3 = 1034`

Here

`num_1`

is the only valid number since it has both 1s and 0s.

`num_2`

is invalid because it does not have any 1s or 0s.

`num_3`

should also be invalid since it has digits other than 0s and 1s which are 2 and 4.Note: you cannot use any

`for`

loops or`while`

loop or any python function or method or string methods or built-in python methods all you can use are`if`

`elif`

and`else`

.

How can we solve this to find the number which has only 1s and 0s in it?

The given integer can be in between the range 0 and 10000.