a = [1, 2, 3, 4, 5, 6, 7, 8, 9]


def counting():
    counter = 0
    while counter < 10:
        print("Hello")
        counter += 1
    else:
        print("Bye!")
    inp = input('If you would like to repeat, press (y) otherwise press (n)')
    while True:
        if inp.lower() == 'y':
            counting()
            break
        elif inp.lower() == 'n':
            menu()
            break
        elif inp != str:
            print('not recognised')
            inp = input('If you would like to repeat, press (y) otherwise press (n)')



def count2():
    li = ['Hello', 'Hello', 'Hello', 'Hello', 'Hello', 'Hello', 'Hello', 'Hello', 'Hello', 'Hello']
    for x in li:
        print (x)
    inp = input('If you would like to repeat, press (y) otherwise press (n)')
    while True:
        if inp.lower() == 'y':
            count2()
            break
        elif inp.lower() == 'n':
            menu()
            break
        elif inp != str:
            print('not recognised')
            inp = input('If you would like to repeat, press (y) otherwise press (n)')


def even():
    for x in range(10, 20):
        even_ = []
        odd_ = []
        if x % 2 == 0:
            even_.append(x)
        else:
            odd_.append(x)
        return even_
    inp = input('If you would like to repeat, press (y) otherwise press (n)')
    while True:
        if inp.lower() == 'y':
            even()
            break
        elif inp.lower() == 'n':
            menu()
            break
        elif inp != str:
            print('not recognised')
            inp = input('If you would like to repeat, press (y) otherwise press (n)')


def prime():
    print('')
    print('This is a function to give you all the pri'
          'e numbers between two numbers you enter')
    print('Type in two numbers and you will get all the prime numbers between the two')
    print('')
    while True:
        try:
            x = int(input('Enter a number: '))
            y = int(input('Enter a last num: '))
            for z in range(x, y):
                p = []
                for n in range(1, z+1):
                    if z % n == 0:
                        p.append(n)
                if len(p) == 2:
                    print(z)
            break
        except ValueError:
            print('Please enter a number')
    while True:
        inp = input('If you would like to repeat, press (y) otherwise press (n)')
        if inp.lower() == 'y':
            prime()
            break
        elif inp.lower() == 'n':
            menu()
            break
        elif inp != str:
            print('not recognised')
            inp = input('If you would like to repeat, press (y) otherwise press (n)')


def pythag():
    while True:
        try:
            first = int(input('Enter a number: '))
            second = int(input('Enter another number: '))
            while True:
                if first != abs(first) or second != abs(second):
                    print('Triangle sides cannot be negative')
                    first = int(input('Enter a number: '))
                    second = int(input('Enter another number: '))
                else:
                    break
            c = first ** 2
            d = second ** 2
            e = c + d
            f = e ** 0.5
            print('The Pythagoras theorem calculation of your numbers is: ', f)
            break
        except ValueError:
            print('That s not a number, try again')
    while True:
        inp = input('If you would like to repeat, press (y) otherwise press (n)')
        if inp.lower() == 'y':
            pythag()
            break
        elif inp.lower() == 'n':
            menu()
            break
        elif inp != str:
            print('not recognised')
            inp = input('If you would like to repeat, press (y) otherwise press (n)')



def menu():
    print('')
    print('A:  Hello Counter')
    print('')
    print('B: Counter 2')
    print('')
    print('C: Find even numbers')
    print('')
    print('D: Prime Number')
    print('')
    print('E: Pythagoras Theorem')
    print('')
    ans = input('Choose a Function: ')
    while True:
            if ans.lower() == 'a':
                counting()
                break
            elif ans.lower() == 'b':
                count2()
                break
            elif ans.lower() == 'c':
                even()
                break
            elif ans.lower() == 'd':
                prime()
                break
            elif ans.lower() == 'e':
                pythag()
            else:
                print('Function not recognised. Please try again')
                ans = input('Choose a function: ')

menu()