Merkkijono

#input string
string = "AAAAAAABBBBBBBBBBBBBBBCCCCBCCCCDDDDBBBBBA"
list1 = list(string)
a = True
while(a):
    for i in xrange(len(list1)-1):
        b = False
        while(list1[i] == list1[i+1]):
            list1.pop(i+1)
            b = True
            if(len(list1) == 1):
                break
        if b:
            list1.pop(i)
            break
        if i == len(list1)-2:
            a = False
    if len(list1)-1 == 0:
        a = False
string = "".join(list1)
print(string)

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