def colnum_string(n):
string = “”
while n > 0:
n, remainder = divmod(n - 1, 26)
string = chr(65 + remainder) + string
return string
print(colnum_string(28))#output:AB

def colnum_string(n):
string = “”
while n > 0:
n, remainder = divmod(n - 1, 26)
string = chr(65 + remainder) + string
return string
print(colnum_string(28))#output:AB