In this example, we will learn how to calculate the sum of all numbers in a given list.

### Source Code

```
#! /usr/bin/env python3
# -*- coding: utf-8 -*-
n = input("Please input a number: ")
a = list(n)
sum = 0
for i in range(len(a)):
sum += int(a[i])
print("The sum is: ", sum)
```

Output:

```
Please input a number: 45623
The sum is: 20
```