销售统计问题：

我们假设这个便利店有四个销售员，他们分别负责五种产品（销售员编号1-4，产品编号1-5）。每个销售员都将当天出售的每种商品单独做个记录。

（1）计算上个月每个人每种产品的销售额；

（2）按销售额对销售员进行排序，输出排序结果（销售代号）；

（3）统计每种产品的总销售额，对这些产品按从高到低的顺序输出排序 结果（需输出产品的代号和销售额）；-Sales statistics: We have assumed that there are four convenience stores sales, they are responsible for the five products (No. 1-4 sales, product No. 1-5). Each salesperson will be on sale the same day to be a separate record of each commodity. (1) were calculated for each month of sales for each product　(2) by the sales ranking of sales, output to sort results (sales code)　(3) statistics of the total sales of each product of these products according to the order of output from high to low sort results (the code takes the output and sales of products)