Write a C program that simulates a parallel task execution scenario using process forking. The program should create a specified number of child processes, each performing a unique task. The parent process should wait for all child processes to complete before displaying the final result.

Requirements:

Your program should take an integer input n from the user, where n represents the number of child processes to be created. n should be less than $5.$

Each child process should perform a different task, such as computing the factorial of a number, finding prime numbers in a range, or any computationally intensive operation.

The parent process should display a message before creating $($forking$)$ the child processes.

Each child process should print its own identifier $($PID$)$ and the task it is performing.

After completing their tasks, each child process should print a completion message.

The parent process should wait for all child processes to finish before displaying a final message.