51. Write a code to generate a aplhabet half pyramid pattern.

Write a code to generate a aplhabet half pyramid pattern.

Input Description:
Given an integer R indicates number of rows.

Where 1<=R<=26.

Output Description:
Print the alphabet half pyramid pattern according to the given integer R.

Sample Input :
5
Sample Output :
ABCDE
 ABCD
  ABC
   AB
    A
    
    
    
    def pattern(n):
    for i in range(n):
        for j in range(i):
            print(' ', end = "")
        for j in range(n-i):
            print(chr(65+j), end = "")
        print()
n = int(input())
pattern(n)