PROGRAMMING:Cyclic greatest common divisor

Finding the greatest common divisor of three integers
###Input format:
Enter three positive integers separated by spaces
###Output format:
Output the greatest common divisor, illegal data is not output
###Input example:
Here is a set of inputs. For example:
```in
10 20 30
```
###Output example:
The corresponding output is given here. For example:
```out
ten
```







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