def convert_to_celsius(temp_str):
    C = (eval(temp_str[0:-1]) - 32)/1.8
    return C

def convert_to_fahrenheit(temp_str):
    F = 1.8*eval(temp_str[0:-1]) + 32
    return F

TempStr = input("请输入带有符号的温度值: ")

if TempStr[-1] in ['F', 'f']:
    C = convert_to_celsius(TempStr)
    print("转换后的温度是{:.2f}C".format(C))
elif TempStr[-1] in ['C', 'c']:
    F = convert_to_fahrenheit(TempStr)
    print("转换后的温度是{:.2f}F".format(F))
else:
    print("输入格式错误")