name=input('what is your name? ')
print('Welcome to ',name)

#this code checks if the user wants the rules or not
while True:
    rules=input('Do you want to see how to play?(yes/no) ').lower()
    if rules in ('yes', 'y'):
        print('                     ---- rules ----')
        print('For Square')
        print('Perimeter = 4 x length')
        print('area= length x length\n')
        print('For Rectangle')
        print('Perimeter = 2 x (width + length)')
        print('area = width x length\n')
        print('For Triangle')
        print('Perimeter = side a + side b + side c')
        print('area = 1⁄2 base x height\n')
        break
    elif rules in ['no','n']:
        print('I hope your good at math then.')
        break
    else:
        print('come again? (yes/no)')
        continue