Inner tube size on a 700c?

Hey everyone, I am ordering parts for my first distance uni soon, and I need to know what the second number in the messurments mean. The only tubes I have ever got are 24 and 20 inch. What size innertube would you guys recamend for the Big Apple? Thoughts appreciated.

you need a 29er sized tube, aka.700x 52 or 700x58

To add to Jagur’s advice, whatever you do, don’t buy a normal 700c x 38 tube from a bike shop. They will tell you that it should work, you’ll then put it in your big apple, and it will explode at the valve.

Whatever the shops say, you really do need a 700c x 52 or bigger tube. Somewhere that knows what a 29er mountain bike is will know what that is.