import sys

input = sys.stdin.readline

from collections import *



N = int(eval(input()))

l = [0, 26]



for i in range(30):

    l.append(l[-1]*26)



for i in range(len(l)):

    if N-l[i]>0:

        N -= l[i]

    else:

        keta = i

        break



ans = []

alpha = 'abcdefghijklmnopqrstuvwxyz'



for i in range(keta):

    for j in range(26):

        if N-pow(26, keta-1-i)>0:

            N -= pow(26, keta-1-i)

        else:

            ans.append(j)

            break



ans2 = []



for i in ans:

    ans2.append(alpha[i])



print((''.join(ans2)))
N = int(eval(input()))



for i in range(1, 100):

    if N<=26**i:

        ans = ''

        N -= 1

        

        for j in range(i):

            ans += chr(ord('a')+N%26)

            N //= 26

            

        break

    else:

        N -= 26**i



print((ans[::-1]))
import sys

input = sys.stdin.readline
from collections import *

N = int(eval(input()))
l = [0, 26]
for i in range(30):
    l.append(l[-1] * 26)
for i in range(len(l)):
    if N - l[i] > 0:
        N -= l[i]
    else:
        keta = i
        break
ans = []
alpha = "abcdefghijklmnopqrstuvwxyz"
for i in range(keta):
    for j in range(26):
        if N - pow(26, keta - 1 - i) > 0:
            N -= pow(26, keta - 1 - i)
        else:
            ans.append(j)
            break
ans2 = []
for i in ans:
    ans2.append(alpha[i])
print(("".join(ans2)))

N = int(eval(input()))
for i in range(1, 100):
    if N <= 26**i:
        ans = ""
        N -= 1
        for j in range(i):
            ans += chr(ord("a") + N % 26)
            N //= 26
        break
    else:
        N -= 26**i
print((ans[::-1]))

-import sys - -input = sys.stdin.readline -from collections import * - -l = [0, 26] -for i in range(30): -    l.append(l[-1] * 26) -for i in range(len(l)): -    if N - l[i] > 0: -        N -= l[i] +for i in range(1, 100): +    if N <= 26**i: +        ans = "" +        N -= 1 +        for j in range(i): +            ans += chr(ord("a") + N % 26) +            N //= 26 +        break -        keta = i -        break -ans = [] -alpha = "abcdefghijklmnopqrstuvwxyz" -for i in range(keta): -    for j in range(26): -        if N - pow(26, keta - 1 - i) > 0: -            N -= pow(26, keta - 1 - i) -        else: -            ans.append(j) -            break -ans2 = [] -for i in ans: -    ans2.append(alpha[i]) -print(("".join(ans2))) +        N -= 26**i +print((ans[::-1]))