PROGRAMMING:Hollow isosceles triangle*

Please write a program to output hollow isosceles triangle.
####Input format
>Number of rows (positive integer)
####Output format
>A hollow isosceles triangle outlined by an asterisk
####Input sample 1
```in
one
```
####Output sample 1
```out
*
```
####Input sample 2
```in
five
```
####Output sample 2
```out
*
* *
* *
* *
****
```







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