Farmer John's Ncows are standing in a row, as they have a tendency to do from time to time. Each cow is labeled with a distinct integer ID number so FJ can tell them apart. FJ would like to take a photo of a contiguous group of cows but, due to a traumatic childhood incident involving the numbers
, he only wants to take a picture of a group of cows if their IDs add up to a multiple of 7.
Please help FJ determine the size of the largest group he can photograph.
给你个数，分别是。
求一个最长的区间，使得区间中的数()的和能被整除。
输出区间长度。若没有符合要求的区间，输出。
输入格式
The first line of input contains N(1<=n<=50000).
The next N lines each contain the N integer IDs of the cows
(all are in the range).
第一行是();
以后的行是()个数。
输出格式
Please output the number of cows in the largest consecutive group whose IDs sum to a multiple of 7.