# -*- coding: iso-8859-1 -*-
# Juhon ikiomaa koodia tämä on
# Lukeeko näitä joku?

#funktiot SPRÖLÖLÖLÖLÖLÖLÖLÖLÖL





    def plussa(a, b):
        c = a + b
        return c

    def miinus(a, b):
        c = a - b
        return c

    def kerto(a, b):
        c = a * b
        return c

    def jakol(a, b):
        if b == 0:
            asd = "Cannot divide by zero."
            return asd
        else:
            c = a / b
            return c









loop = True


while loop:
    print '(a)dd, (s)ubstract, (m)ultiply, (d)ivide, (q)uit'
    valinta = raw_input('Give an operation: ')



    if valinta == 'a':
        n1 = float(raw_input('First number: '))
        n2 = float(raw_input('Second number: '))
        paska = plussa(n1, n2)
        print paska
        main()

    elif valinta == 's':
        n1 = float(raw_input('First number: '))
        n2 = float(raw_input('Second number: '))
        paska = miinus(n1,n2)
        print paska

    elif valinta == 'm':
        n1 = float(raw_input('First number: '))
        n2 = float(raw_input('Second number: '))
        paska = kerto(n1,n2)
        print paska

    elif valinta == 'd':
        n1 = float(raw_input('First number: '))
        n2 = float(raw_input('Second number: '))
        paska = jakol(n1,n2)
        print paska

    elif valinta == 'q':
         loop = False


    else:
        print 'WHAT ARE YOU DOING?'