Print Isosceles Alphabet Triangle

Given a positive integer \(n\) (\(1 \le n \le 26\)), print an isosceles triangle consisting of the first \(n\) uppercase English letters. The first row contains the letter 'A', the second row contains two 'B's separated by a single space, and so on. Each row must be centered within a fixed width of \(2n-1\) characters.

Example 1:

Input:
4
Output:
A

B B

C C C
D D D D

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Example 2:

Input:
1
Output:
A

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Make sure your solution reads input from stdin and outputs the result to stdout.

inputFormat

The input is a single integer \(n\) which represents the number of rows in the triangle. It is guaranteed that \(1 \le n \le 26\).

outputFormat

The output should be an isosceles triangle of alphabets with \(n\) rows. Each row should have exactly \(2n-1\) characters (including spaces) so that the letters are centered.

## sample

4

   A   
B B

C C C
D D D D

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