import sys

input = sys.stdin.readline

import string

import sys

import math



ALPHABET = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]

result = []



def alphabet_decimal(v):

    quotient = math.floor(v / len(ALPHABET))

    surplus = v % len(ALPHABET)

    quotient -= 1 if surplus == 0 else 0

    surplus = len(ALPHABET) if surplus == 0 else surplus

    result.append(surplus)

    if len(ALPHABET) < quotient:

        alphabet_decimal(quotient)

    elif len(ALPHABET) < v:

        result.append(quotient)

    return "".join([ALPHABET[i - 1] for i in reversed(result)])

def main():

    N = int(eval(input()))

    ans = alphabet_decimal(N).lower()

    print(ans)

if __name__ == "__main__":

    main()
import sys

input = sys.stdin.readline

import string

def main():

    def f(n):

        if n == -1:return

        a, b = divmod(n, 26)

        ans.append(string.ascii_lowercase[b])

        f(a-1)



    N = int(eval(input()))

    ans = []

    f(N-1)

    print(("".join(ans[::-1])))

if __name__ == "__main__":

    main()
import sys

input = sys.stdin.readline
import string
import sys
import math

ALPHABET = [
    "A",
    "B",
    "C",
    "D",
    "E",
    "F",
    "G",
    "H",
    "I",
    "J",
    "K",
    "L",
    "M",
    "N",
    "O",
    "P",
    "Q",
    "R",
    "S",
    "T",
    "U",
    "V",
    "W",
    "X",
    "Y",
    "Z",
]
result = []


def alphabet_decimal(v):
    quotient = math.floor(v / len(ALPHABET))
    surplus = v % len(ALPHABET)
    quotient -= 1 if surplus == 0 else 0
    surplus = len(ALPHABET) if surplus == 0 else surplus
    result.append(surplus)
    if len(ALPHABET) < quotient:
        alphabet_decimal(quotient)
    elif len(ALPHABET) < v:
        result.append(quotient)
    return "".join([ALPHABET[i - 1] for i in reversed(result)])


def main():
    N = int(eval(input()))
    ans = alphabet_decimal(N).lower()
    print(ans)


if __name__ == "__main__":
    main()

import sys

input = sys.stdin.readline
import string


def main():
    def f(n):
        if n == -1:
            return
        a, b = divmod(n, 26)
        ans.append(string.ascii_lowercase[b])
        f(a - 1)

    N = int(eval(input()))
    ans = []
    f(N - 1)
    print(("".join(ans[::-1])))


if __name__ == "__main__":
    main()

-import sys -import math - -ALPHABET = [ -    "A", -    "B", -    "C", -    "D", -    "E", -    "F", -    "G", -    "H", -    "I", -    "J", -    "K", -    "L", -    "M", -    "N", -    "O", -    "P", -    "Q", -    "R", -    "S", -    "T", -    "U", -    "V", -    "W", -    "X", -    "Y", -    "Z", -] -result = [] - - -def alphabet_decimal(v): -    quotient = math.floor(v / len(ALPHABET)) -    surplus = v % len(ALPHABET) -    quotient -= 1 if surplus == 0 else 0 -    surplus = len(ALPHABET) if surplus == 0 else surplus -    result.append(surplus) -    if len(ALPHABET) < quotient: -        alphabet_decimal(quotient) -    elif len(ALPHABET) < v: -        result.append(quotient) -    return "".join([ALPHABET[i - 1] for i in reversed(result)]) +    def f(n): +        if n == -1: +            return +        a, b = divmod(n, 26) +        ans.append(string.ascii_lowercase[b]) +        f(a - 1) + -    ans = alphabet_decimal(N).lower() -    print(ans) +    ans = [] +    f(N - 1) +    print(("".join(ans[::-1])))