Isosceles Triangle of Stars

Problem Description

The right triangle from before only asked you to control how many stars each row printed; an isosceles triangle also needs leading spaces, which makes it a classic first exercise on nested loops: the outer loop walks over the rows, while the inner loops handle the spaces and then the stars of that row.

Concretely, for a triangle with $n$ rows, row $i$ ($1 \le i \le n$) must:

• print $n-i$ spaces first;
• then print $2i-1$ copies of *;
• then move to the next line.

For example, with $n=3$:

  *
 ***
*****

Read $n$ and print the corresponding isosceles triangle.

Input Format

One line containing a positive integer $n$.

Output Format

$n$ lines forming the triangle exactly as described. The number of leading spaces on each line must follow the rule exactly.

Sample Input

3

Sample Output

  *
 ***
*****

Constraints

For 100% of the test data, $1 \le n \le 30$.

Hint: you may write two nested loops, or think of it in terms of string(n - i, ' '). Note that the last row (row $n$) has no leading spaces.