Write a Python function to compute the remaining passengers on a bus after covering all stations.
Given a route of a bus traveling through numerous stations in a city, the bus registers passengers getting on and off at each station. The commute data is represented as a 2D list, where each sublist corresponds to a bus station and contains the number of passengers getting on (first element) and getting off (second element) at that station. Write a function named `remaining_passengers` that accepts this list and returns the total count of passengers remaining on the bus at the end of the route - those who either fell asleep or missed their stop. ### Parameters - `bus_stations` (list): A list composed of 'n' sublists, where each sublist includes two integers - the number of passengers boarding and alighting from the bus at a particular station. Here, 'n' (1<=n<=1000) denotes the number of stations in total. ### Return Value - The function should return an integer that signifies the total number of passengers left on the bus after all stations have been covered. ### Examples ```python # 10 boarded and 0 alighted, then 3 boarded and 5 alighted, and finally 5 boarded and 8 alighted # 10 - 0 + 3 - 5 + 5 - 8 = 5 remaining_passengers([[10,0],[3,5],[5,8]]) # Returns: 5 remaining_passengers([[3,0],[9,1],[4,10],[12,2],[6,1],[7,10]]) # Returns: 17 remaining_passengers([[3,0],[9,1],[4,8],[12,2],[6,1],[7,8]]) # Returns: 21 ```