while True:
    x = float(input('请输入数值'))
    y = float(input('请输入数值'))
    z = input('请输入+,-,*,/')

    if z =='+':
        print(x+y)
    elif z == '-':
        print(x-y)
    elif z == '*':
        print(x*y)
    elif z == '/':
        print(x/y)




