n=int(eval(input()))

ans=""

for l in range(1,15):

  if n<=26**l:

    n-=1

    for j in range(l):

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

      n//=26

    break

  else:

    n-=26**l

    

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

    
n=int(eval(input()))



tmp=0

for ll in range(1,20):

  tmp+=26**ll

  if n<=tmp:

    break



s=chr((n-1)%26+ord("a")) ##一文字目

for i in range(1,ll):

  n-=26**i

  s+=chr((n-1)//(26**i)%26+ord("a")) 



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

n = int(eval(input()))
ans = ""
for l in range(1, 15):
    if n <= 26**l:
        n -= 1
        for j in range(l):
            ans += chr(ord("a") + n % 26)
            n //= 26
        break
    else:
        n -= 26**l
print((ans[::-1]))

n = int(eval(input()))
tmp = 0
for ll in range(1, 20):
    tmp += 26**ll
    if n <= tmp:
        break
s = chr((n - 1) % 26 + ord("a"))  ##一文字目
for i in range(1, ll):
    n -= 26**i
    s += chr((n - 1) // (26**i) % 26 + ord("a"))
print((s[::-1]))

-ans = "" -for l in range(1, 15): -    if n <= 26**l: -        n -= 1 -        for j in range(l): -            ans += chr(ord("a") + n % 26) -            n //= 26 +tmp = 0 +for ll in range(1, 20): +    tmp += 26**ll +    if n <= tmp: -    else: -        n -= 26**l -print((ans[::-1])) +s = chr((n - 1) % 26 + ord("a"))  ##一文字目 +for i in range(1, ll): +    n -= 26**i +    s += chr((n - 1) // (26**i) % 26 + ord("a")) +print((s[::-1]))