PROGRAMMING:sum of digits of a number
Write a program in C to find the sum of digits of a number using recursion.
### Input：
Input one positive integer.
### Output:
Print the sum of digits of the input number.
### Input sample:
```in
eighty-seven
```
### Output sample:
```out
fifteen
```
answer：If there is no answer, please comment
### Input：
Input one positive integer.
### Output:
Print the sum of digits of the input number.
### Input sample:
```in
eighty-seven
```
### Output sample:
```out
fifteen
```
answer：If there is no answer, please comment
