user_turns: <SILENCE> cheap restaurant center <SILENCE> vietnamese food <SILENCE> food vietnamese food north <SILENCE> center <SILENCE> east <SILENCE> north east <SILENCE> center <SILENCE> moderate <SILENCE> north <SILENCE> east <SILENCE> thank you goodbye
system_turns: Hello , welcome to the Cambridge restaurant system . You can ask for restaurants by area , price range or food type . How may I help you ? What part of town do you have in mind? What kind of food would you like? You are looking for a restaurant is that right? api_call R_cuisine R_location cheap the_missing_sock is a nice restaurant in the east of town in the cheap price range Can I help you with anything else? Sorry there is no cheap restaurant in the east of town serving vietnamese food api_call vietnamese north cheap Sorry there is no cheap restaurant in the north of town serving vietnamese food api_call vietnamese west cheap Sorry there is no cheap restaurant in the centre of town serving vietnamese food api_call vietnamese east cheap Sorry there is no cheap restaurant in the east of town serving vietnamese food api_call vietnamese south cheap Sorry there is no cheap restaurant in the north of town serving vietnamese food api_call vietnamese west cheap Sorry there is no cheap restaurant in the centre of town serving vietnamese food api_call vietnamese west moderate Sorry there is no moderate restaurant in the centre of town serving vietnamese food api_call vietnamese north moderate Sorry there is no moderate restaurant in the north of town serving vietnamese food api_call vietnamese east moderate Sorry there is no moderate restaurant in the east of town serving vietnamese food  you are welcome