Merkkijono

import re
import sys

for a in sys.stdin.read().splitlines():
    while True:
        b = re.sub(r'(.)\1+', '', a, 1)
        if a == b:
            break
        a = b
    print(a)

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