Draw a Triangle

Problem Description

Given a positive integer $n$, use uppercase letters to draw a triangle pattern as shown in the sample input/output. The first row of the triangle has $1$ letter, the second row has $2$ letters, and so on. In the triangle pattern, from top to bottom and from left to right, fill successively with the uppercase letters A–Z; after using Z, restart filling from A.

Input Format

One line containing a positive integer $n$. It is guaranteed that $2 \le n \le 40$.

Output Format

Output the triangle pattern as required. Note that there must be no trailing spaces at the right side of each row.

Sample Input

3

Sample Output

A
BC
DEF

Sample Explanation

When $n = 3$, the triangle has $3$ rows. The first row has $1$ letter, which is A; the second row has $2$ letters, in order B and C; the third row has $3$ letters, in order D, E and F. Hence the output is as shown above.

Constraints

$2 \le n \le 40$