Write a C program using Pthreads on Linux that acts like a countdown timer alarm: The program implements a timer with two threads When the program starts, prompt the user for a number of seconds to set the timer (look into using scanf() to do this) Start two threads: 

1. A thread that waits for a notification that the timer expired; when the timer expires, this thread should print a message that the timer has expired 

2. A thread that will wait for the specified number of seconds (look into sleep() for this) and then sends a notification to the other thread that the timer has expired