Merkkijono

query = input()

def trimQuery(q):
    tempq = ""
    while(tempq != q and len(q) > 0):
        tempq = q
        q = removeFirstPattern(q)
        
    return q

def removeFirstPattern(q):
    start = 0
    end = 0
    current = q[0]
    if len(q) > 1:
        for n in range(1, len(q)):
            if q[n] == current:
                end = n
            elif end > 0:
                return q[:start] + q[end + 1:]
            else:
                start = n
                current = q[n]
    if end > 0:
        return q[:start] + q[end + 1:]
    else:
        return q
                

print(trimQuery(query))

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