Each pair of cities in Wonderland is connected by a flight operated by "Wonderland Airlines". How many cities are there in the country if there are \(105\) different flights? We count a flight from city \(A\) to city \(B\) as the same as city \(B\) to city \(A\) - i.e. the pair \(A\) to \(B\) and \(B\) to \(A\) counts as one flight.