Merkkijono

string = str(input())
list1 = list(string)
a = True
while a:
    for i in range(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: ACCEPTED

Test 2

Verdict: TIME LIMIT EXCEEDED

Test 3

Verdict: TIME LIMIT EXCEEDED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 7, in <module>
    while list1[i] == list1[i+1]:
IndexError: list index out of range

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED