Merkkijono

import string
def s(n, middle_index):
    if n == 1:
        return str(middle_index)
    return s(n-1, middle_index+1)+str(middle_index)+s(n-1, middle_index+1)
def conv(s):
    letters = string.ascii_lowercase
    return "".join([letters[int(i)] for i in s])
print(conv(s(int(input()), 0)))
if __name__ == "__main__":
    for i in range(1, 16):
        print(conv(s(i, 0)))

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: WRONG ANSWER

Test 14

Verdict: WRONG ANSWER

Test 15

Verdict: WRONG ANSWER

Test 16

Verdict: WRONG ANSWER