while True:
    TemStr=input("请输入带符号的温度值:")
    if TemStr[-1] in ['F','f']:
        C = (eval(TemStr[0:-1]) -32)/1.8
        print("转换后的温度：{0:.2f}C".format(C))
    elif TemStr[-1] in ['C','c']:
        F = 1.8*eval(TemStr[0:-1])+32
        print("转换后的温度是；{0:.2f}F".format(F))
    else:
        print("输入格式错误")