Device Connectivity

In a network of devices, some devices are directly connected while others are not. Given a list of connections between devices, your task is to determine how many devices can be reached from a given starting device through direct connections. Input format: - The first line contains two integers n (1 <= n <= 1000) and m (0 <= m <= 2000), where n is the number of devices and m is the number of connections. - The next m lines each contain two integers a and b (1 <= a, b <= n), indicating that device a is connected to device b. - The last line contains a single integer d (1 <= d <= n), the starting device. Output format: - Output a single integer representing how many devices can be reached from device d. Example: Input: 5 4 1 2 2 3 1 4 4 5 1 Output: 5