#do math

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

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

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

if __name__ == "__main__":
    print("Welcome to my math program")

    choice = "z"
    while choice != "q":
        choice = input("[a]dd, [s]ubtract, [m]ultiply, [q]uit? ")
        
        if choice != "q":
            a= int(input("first number:" ))
            b = int(input("second number:" ))
            
            if choice == "a":
                print(add(a,b))
            elif choice == "s":
                print(subtract(a,b))
            elif choice == "m":
                print(multiply(a,b))
            
print("goodbye!")