name = input('What is your name? ')
print('Hello ', name + '!')           # concatenate exclamation point

print('I will compute the hypotenuse of a right triangle.')
print('But first, you must tell me the lengths of the legs.')
a = float(input('What is the length of the first leg? '))
b = float(input('What is the length of the second leg? '))
c = (a**2 + b**2) ** 0.5
print('The length of the hypotenuse is', str(c) + '.')