import sys

input = sys.stdin.readline

sys.setrecursionlimit(10 ** 7)



n = int(eval(input()))



import string

from collections import deque



name_table = 'z' + string.ascii_lowercase

ans = deque()





while n > 0:

    q = n // 26

    m = n % 26

    ans.appendleft(name_table[m])

    if m == 0:

        n = q - 1

    else:

        n = q



print((''.join(ans)))

import sys

input = sys.stdin.readline

sys.setrecursionlimit(10 ** 7)



n = int(eval(input()))



import string

from collections import deque



name_table = string.ascii_lowercase

ans = deque()





while n > 0:

    n -= 1

    m = n % 26

    ans.appendleft(name_table[m])

    n //= 26



print((''.join(ans)))

import sys

input = sys.stdin.readline
sys.setrecursionlimit(10**7)
n = int(eval(input()))
import string
from collections import deque

name_table = "z" + string.ascii_lowercase
ans = deque()
while n > 0:
    q = n // 26
    m = n % 26
    ans.appendleft(name_table[m])
    if m == 0:
        n = q - 1
    else:
        n = q
print(("".join(ans)))

import sys

input = sys.stdin.readline
sys.setrecursionlimit(10**7)
n = int(eval(input()))
import string
from collections import deque

name_table = string.ascii_lowercase
ans = deque()
while n > 0:
    n -= 1
    m = n % 26
    ans.appendleft(name_table[m])
    n //= 26
print(("".join(ans)))

-name_table = "z" + string.ascii_lowercase +name_table = string.ascii_lowercase -    q = n // 26 +    n -= 1 -    if m == 0: -        n = q - 1 -    else: -        n = q +    n //= 26