Merkkijono

l = list(raw_input().upper())
z = 0
y = len(l)
x = 0
a = 0
while x < len(l)+1000:
  if (z+1) < len(l):
    while l[z] == l[z+1]:
      del l[z]
      a = 1
    if a == 1:
      del l[z]
      a = 0
      z = -1
    z += 1  
  x += 1
s = ""
print s.join(l)

Test 1

Verdict: ACCEPTED

Test 2

Verdict: RUNTIME ERROR

Traceback (most recent call last):
  File "input/code.py", line 8, in <module>
    while l[z] == l[z+1]:
IndexError: list index out of range

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: ACCEPTED

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