n=int(eval(input()))

ans=''

alpha='abcdefghijklmnopqrstuvwxyza'

while n>0:

    n-=1

    ans+=alpha[n%26]

    n//=26

print((ans[::-1]))
n=int(eval(input()))

keta=[26]

t=2

while keta[-1]<10**15+1:

    keta.append(keta[-1]+26**t)

    t+=1

#print(keta)



import bisect,sys

nagasa=bisect.bisect_left(keta,n)+1

#print(nagasa)



alpha='abcdefghijklmnopqrstuvwxyza'

if nagasa==1:

    print((alpha[n-1]))

    sys.exit()



n-=keta[nagasa-2]

n-=1



ans=''

L=[]

while n>0:

    L.append(n%26)

    n//=26

while len(L)<nagasa:

    L.append(0)

for i in L:

    ans+=alpha[i]

print((ans[::-1]))
n = int(eval(input()))
ans = ""
alpha = "abcdefghijklmnopqrstuvwxyza"
while n > 0:
    n -= 1
    ans += alpha[n % 26]
    n //= 26
print((ans[::-1]))

n = int(eval(input()))
keta = [26]
t = 2
while keta[-1] < 10**15 + 1:
    keta.append(keta[-1] + 26**t)
    t += 1
# print(keta)
import bisect, sys

nagasa = bisect.bisect_left(keta, n) + 1
# print(nagasa)
alpha = "abcdefghijklmnopqrstuvwxyza"
if nagasa == 1:
    print((alpha[n - 1]))
    sys.exit()
n -= keta[nagasa - 2]
n -= 1
ans = ""
L = []
while n > 0:
    L.append(n % 26)
    n //= 26
while len(L) < nagasa:
    L.append(0)
for i in L:
    ans += alpha[i]
print((ans[::-1]))

+keta = [26] +t = 2 +while keta[-1] < 10**15 + 1: +    keta.append(keta[-1] + 26**t) +    t += 1 +# print(keta) +import bisect, sys + +nagasa = bisect.bisect_left(keta, n) + 1 +# print(nagasa) +alpha = "abcdefghijklmnopqrstuvwxyza" +if nagasa == 1: +    print((alpha[n - 1])) +    sys.exit() +n -= keta[nagasa - 2] +n -= 1 -alpha = "abcdefghijklmnopqrstuvwxyza" +L = [] -    n -= 1 -    ans += alpha[n % 26] +    L.append(n % 26) +while len(L) < nagasa: +    L.append(0) +for i in L: +    ans += alpha[i]