Codeforces Round 350 (Div. 2)
B
Game of Robots
Codeforces
1000
原题
← AC →
翻译中…

In late autumn evening $*n*$ robots gathered in the cheerful company of friends. Each robot has a unique identifier — an integer from $1$ to $10^{9}$.

翻译中…

At some moment, robots decided to play the game "Snowball". Below there are the rules of this game. First, all robots stand in a row. Then the first robot says his identifier. After that the second robot says the identifier of the first robot and then says his own identifier. Then the third robot says the identifier of the first robot, then says the identifier of the second robot and after that says his own. This process continues from left to right until the $*n*$-th robot says his identifier.

翻译中…

Your task is to determine the $*k*$-th identifier to be pronounced.

翻译中…

Input

翻译中…

The first line contains two positive integers $*n*$ and $*k*$ ($1 ≤ *n* ≤ 100 000$, $1 ≤ *k* ≤ *min*(2·10^{9}, *n*·(*n* + 1) / 2$).

翻译中…

The second line contains the sequence $*id*_{1}, *id*_{2}, ..., *id*_{*n*}$ ($1 ≤ *id*_{*i*} ≤ 10^{9}$) — identifiers of roborts. It is guaranteed that all identifiers are different.

翻译中…

Output

翻译中…

Print the $*k*$-th pronounced identifier (assume that the numeration starts from $1$).

翻译中…

Note

翻译中…

In the first sample identifiers of robots will be pronounced in the following order: $1$, $1$, $2$. As $*k* = 2$, the answer equals to $1$.

翻译中…

In the second test case identifiers of robots will be pronounced in the following order: $10$, $10$, $4$, $10$, $4$, $18$, $10$, $4$, $18$, $3$. As $*k* = 5$, the answer equals to $4$.

翻译中…

样例

Input #1
2 2
1 2
Output #1
1
InputCopy OutputCopy
Input #2
4 5
10 4 18 3
Output #2
4
InputCopy OutputCopy
题目信息
题号
670B
时间限制
1 s
内存限制
256 MB
标签
模拟

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。