输入的每一行是两个十进制的正整数和一个运算符，每个整数可以由最多 500 个数字组成。运算符可以是加号或者减号。对应着输入的每一行数据，输出计算的结果，每个结果占一行。-Enter each line of the two decimal positive integer and an operator, each integer can be up to 500 digits. Operator can be plus or minus sign. Corresponding to each line of data input and output calculation results, each result line.