Write a C program that reads two hexadecimal values from the keyboard and then stores the two values into two variables of type unsigned char. Read two int values p and k from the keyboard, where the values are less than 8. Replace the n bits of the first variable starting at position p with the last n bits of the second variable. The rest of the bits of the first variable remain unchanged. Display the resulting value of the first variable using printf %x.

Test Cases:

n = 3;p=4;input: a= 0x1f (0001 1111) b = c3 (1100 0011); output: f (0000 1111)

n = 2;p=5;input: a= 0x1f (0001 1111) b = c3 (1100 0011); output: 3f (0011 1111)