i am looking for a cheap restaurant near the centre of cambridge .
{'service': 'restaurant', 'act': 'request', 'slot_name': 'food', 'value': '?'} {'service': 'restaurant', 'act': 'inform', 'slot_name': 'choice', 'value': '15'}
there are 15 restaurant -s that meet your needs . would you like to narrow it down by cuisine ?