A. Arya and Bran

time limit per test:1 second

memory limit per test:256 megabytes

input:standard input

output:standard output

Bran and his older sister Arya are from the same house. Bran like candies so much, so Arya is going to give him some Candies.

At first, Arya and Bran have 0 Candies. There are n days, at the i-th day, Arya finds ai candies in a box, that is given by the Many-Faced God. Every day she can give Bran at most 8 of her candies. If she don't give him the candies at the same day, they are saved for her and she can give them to him later.

Your task is to find the minimum number of days Arya needs to give Bran k candies before the end of the n-th day. Formally, you need to output the minimum day index to the end of which k candies will be given out (the days are indexed from 1 to n).

Print -1 if she can't give him k candies during n given days.

Input

The first line contains two integers n and k (1 ≤ n ≤ 100, 1 ≤ k ≤ 10000).

The second line contains n integers a1, a2, a3, ..., an (1 ≤ ai ≤ 100).

Output

If it is impossible for Arya to give Bran k candies within n days, print -1.

Otherwise print a single integer — the minimum number of days Arya needs to give Bran k candies before the end of the n-th day.

Examples

Input

2 3
1 2

Output

2

Input

3 17
10 10 10

Output

3

Input

1 9
10

Output

-1

Note

In the first sample, Arya can give Bran 3 candies in 2 days.

In the second sample, Arya can give Bran 17 candies in 3 days, because she can give him at most 8 candies per day.

In the third sample, Arya can't give Bran 9 candies, because she can give him at most 8 candies per day and she must give him the candies within 1 day.

题目链接：http://codeforces.com/contest/839/problem/A

分析：题意大概是第n天结束之前需要给予Bran k糖果的最少天数，暴力即可，不过这题目题意确实有点迷就是了！

下面给出AC代码：

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 int main()
 4 {
 5     int n,m;
 6     cin>>n>>m;
 7     int ans=0;
 8     for(int i=1;i<=n;i++)
 9     {
10         int x;
11         cin>>x;
12         ans+=x;
13         m-=min(ans,8);
14         ans-=min(ans,8);
15         if(m<=0)
16             return !printf("%dn",i);
17     }
18     return !printf("-1n");
19 }