Employee Shift Scheduling

You are tasked with scheduling employee shifts based on their availability. Each employee has a range during which they can work, defined by start and end times. Your goal is to determine how many employees can be assigned to shifts without overlapping their available times. Input format: The first line contains an integer n (1 <= n <= 1000), the number of employees. The next n lines each contain two integers representing the available start and end times of each employee (0 <= start < end <= 24). Output format: Print a single integer, the maximum number of employees that can be assigned shifts without overlap. Example: Input: 4 1 4 2 5 3 6 4 7 Output: 2