import sys

read = sys.stdin.read

readline = sys.stdin.readline

readlines = sys.stdin.readlines



def main():

    N = int(readline())

    

    ans = ''

    while N:

        if N % 26 == 0:

            ans += "z"

            N -= 1

            N //= 26

        else:

            ans += chr((N % 26) -1  + 97)

            N //= 26



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



if __name__ == "__main__":

    main()

import sys

read = sys.stdin.read

readline = sys.stdin.readline

readlines = sys.stdin.readlines



def main():

    N = int(readline())

    

    ans = ''

    while N:

        N -= 1

        ans += chr((N % 26) + 97)

        N //= 26



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



if __name__ == "__main__":

    main()

import sys

read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines


def main():
    N = int(readline())
    ans = ""
    while N:
        if N % 26 == 0:
            ans += "z"
            N -= 1
            N //= 26
        else:
            ans += chr((N % 26) - 1 + 97)
            N //= 26
    print((ans[::-1]))


if __name__ == "__main__":
    main()

import sys

read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines


def main():
    N = int(readline())
    ans = ""
    while N:
        N -= 1
        ans += chr((N % 26) + 97)
        N //= 26
    print((ans[::-1]))


if __name__ == "__main__":
    main()

-        if N % 26 == 0: -            ans += "z" -            N -= 1 -            N //= 26 -        else: -            ans += chr((N % 26) - 1 + 97) -            N //= 26 +        N -= 1 +        ans += chr((N % 26) + 97) +        N //= 26