Train Station Arrival

At a busy train station, trains arrive at designated times and stay for a certain duration. The station can only accommodate one train at a time. Implement a program that manages the train arrivals and calculates how many trains can be served in a given time period. The input consists of multiple lines each containing two integers: the arrival time of the train and its length of stay. The program ends when EOF is reached. Output the total count of trains served within the time period. Example Input: 1 3 2 5 6 3 Example Output: 2