# -*- coding: iso-8859-1 -*-


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

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

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

def divide(a, b):
    if b != 0:
        c = a / b
        return c
    else:
        print "Cannot divide by zero."
        return None


def main():
    loop = True
    while loop:
        print "(a)dd, (s)ubtract, (m)ultiply, (d)ivide, (q)uit"
        operation = raw_input("Give an operation: ")

        if operation == "q":
            loop = False

        elif operation in ("a", "s", "m", "d"):
            first = float(raw_input("First number: "))
            second = float(raw_input("Second number: "))


            if operation == "a":
                tulos = add(first, second)
                print "%.1f" %(tulos)
                continue

            elif operation == "s":
                tulos = subtract(first, second)
                print "%.1f" %(tulos)
                continue

            elif operation == "m":
                tulos = multiply(first, second)
                print "%.1f" %(tulos)
                continue

            elif operation == "d":
                tulos = divide(first, second)
                if tulos == (None):
                    continue
                else:
                    print "%.1f" %(tulos)
                    continue


        else:
            print "WHAT ARE YOU DOING?"
            continue


if __name__ == '__main__':
    main()