Need a code written in Visual basic. Must display answer when button pressed in a textbox for part B and C

CODE B: Definition: The Euler "phi" function, (n), is defined to be the number of integers in {1,2,3,,n1} that are relatively prime to n. Write a FRIENDLY program that uses a function called "Euler" to return the value of (n) for an input value of n. You can use the following algorithm: count =0 for i=1 to n1 if gcd(i,n)=1, then count +=1 return ???' What should it return? alculation by hand preparation for CODE C: Determine whether i) 5 is invertible in Z13 or not, and if 0, what its inverse is; ii) Similarly for 5 in Z15;;iii) Similarly for 5 in Z16 ODE C: Write a FRIENDLY program that (i) allows a user to input two numbers e and n, and then (ii) isplays a message saying that e doesn't have an inverse in Zn or displays a message giving the inverse fe in Zn