Merkkijono

inputti = input("")
n = []
edellinen = ""
oikea = ""
for i in inputti:
    n.append(i)
i = 0
while True:
    try:
        if n[i] == edellinen and n[i] != oikea:
            oikea = n[i]
            del n[i-1]
            del n[i-1]
            i -= 1
        elif n[i] == edellinen and n[i] == oikea:
            del n[i]
        elif n[i] != edellinen and oikea != "":
            oikea = ""
            edellinen = ""
            i = 0
        elif n[i] != edellinen:
            edellinen = n[i]
            i += 1
    except IndexError:
        break
n = "".join(n)
print(n)

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