import io
import sys

sys.stdin = io.StringIO('edda')
sys.stdin = io.StringIO('sdfhhhhcvhhxcxnnnnshh')

s_in = f"EMPTY{input()}"
while True:
    flag = True
    del_index = set()
    for i in range(5, len(s_in) - 1):
        if s_in[i - 1] == s_in[i] and s_in[i] != s_in[i + 1]:
            del_index.add(i)
            del_index.add(i + 1)
        elif s_in[i - 1] != s_in[i] and s_in[i] == s_in[i + 1]:
            del_index.add(i - 1)
            del_index.add(i)

    if del_index:
        flag = False

    s = ''
    for idx, ch in enumerate(s_in):
        if idx in del_index:
            continue

        s += ch

    s_in = s
    if flag:
        break

print(s_in if s_in == 'EMPTY' else s_in.replace('EMPTY', ''))