Fasting with Smokers

I have a question :

If someone is fasting and he is sitting with some of his friends who are smoking. Should he leave them or stay with them ?
Because we know that the smoke of the cigarettes can ruin your fasting.

As long as you do not intentionally inhale the smoke, it does not break your fast. But if you feel disturbed by your friend's cigarette smoke, it's better if you tell your friend that you are fasting. They will understand.