# please use positive value def convertDecimal( num, \ decimal, \ characters = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ", \ lowercharacter=False \ ): # decimal only can use 2 to 36 if num <= 0 and not 2 <= decimal <= 36: return None ret = "" while num > 0: ret = characters[num % decimal] + ret num //= decimal return ret def solve(num): cnt = 1 while num > 26 ** cnt: num -= 26 ** cnt cnt += 1 return convertDecimal(num, 26, "ABCDEFGHIJKLMNOPQRSTUVWXYZ") if __name__=="__main__": print(solve(int(input())))