Wildlife Snapshot

You are setting up automated cameras to capture photos of endangered lynx. You have a list of time intervals [S[i], E[i]] when a lynx is known to be active at a watering hole. A single camera snapshot at time T captures all active lynx whose intervals include T (S[i] <= T <= E[i]). What is the minimum number of snapshots needed to capture every lynx activity at least once? Input Format: The first line contains N, the number of intervals. The next N lines contain two integers S[i] and E[i]. Output Format: A single integer representing the minimum snapshots. Example: Input: 3 1 5 2 3 4 6 Output: 2 Explanation: A snapshot at time 3 covers [1,5] and [2,3]. A snapshot at 6 covers [4,6].