Merkkijono

list = ["a"]
alphabet_list = ["b","c","d","e","f","g","h","i","j","k","l","m","n","o","p"]
x = int(input())
n = x
i = 2
c = 0
while n > 1:
    b = 0
    while b < i:
        list.insert((b*2), alphabet_list[c])
        b += 1
    i = 2 * i
    n -=1
    c += 1
string = ""
for letter in list:
    string += letter
print(string)

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED