import re
String = ''.join('%s\x08%s' % (c, c) for c in 'hello')
String += ' '
String += ''.join('%s\x08_' % c for c in 'world!')
print('Input:', String)
String = re.sub(r'(.)\x08(\1|_)', r'\1', String)
print('Output:', String)
aW1wb3J0IHJlCgpTdHJpbmcgPSAnJy5qb2luKCclc1x4MDglcycgJSAoYywgYykgZm9yIGMgaW4gJ2hlbGxvJykKU3RyaW5nICs9ICcgJwpTdHJpbmcgKz0gJycuam9pbignJXNceDA4XycgJSBjIGZvciBjIGluICd3b3JsZCEnKQoKcHJpbnQoJ0lucHV0OicsIFN0cmluZykKClN0cmluZyA9IHJlLnN1YihyJyguKVx4MDgoXDF8XyknLCByJ1wxJywgU3RyaW5nKQoKcHJpbnQoJ091dHB1dDonLCBTdHJpbmcp