{29.848584,121.560496}+514801={43.825611,87.616804}
{30.682738,103.856839}+(-38630)={18.750260,109.173055}
{39.763587,116.553698}+?={31.229660,121.485670}

问号中应是什么数字？提示：longitude latitude; one kind of codes