In this example, we will learn how to calculate the prime factor(s) of a given integer in Python.

### Source Code

```
#! /usr/bin/env python3
# -*- coding: utf-8 -*-
n = int(input("Please input an integer: "))
print("Its prime factors are: ")
for i in range(1, n+1):
if n % i == 0:
k = 0
for j in range(1, i+1):
if i % j == 0:
k = k + 1
if k == 2:
print(i)
```

Output:

```
Please input an integer: 28
Its prime factors are:
2
7
Please input an integer: 189
Its prime factors are:
3
7
```

I think it would be better if you add some comments to explain the steps. Thanks!