Merkkijono

def main():
    n = int(input())
    i = 1
    kirjaimet = "abcdefghijklmnopqrst5uvwyzåäö"
    vastaus = "a"

    while i < n:
        vastaus = Add(vastaus, i, kirjaimet)
        i += 1 
    print(vastaus)

def Add(jono, luku, kirjaimet):
    uusjono = ""
    i = 0
    while i < len(jono):
        uusjono += kirjaimet[luku]
        uusjono += jono[i]
        i += 1
    uusjono += kirjaimet[luku]

    
    return uusjono

main()

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