说明：  对给定的由N个自然数组成的多重集合S，计算S的众数及其重数。 数据输入：输入数据由文件名input.txt的文本文件提供。文件的第一行为多重集S中元素个数N；在接下来的N行中，每行有一个自然数
(Given by N a natural number composed of multiple sets S, S, plural calculating its multiplicity. Data input: input data from the file name input.txt text document. Multiple sets of the first acts of the file number of elements in S N in the next N lines, each line has a natural number)