First Position of x

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Given an integer array $A=(a_0,a_1,\ldots,a_{n-1})$ and an integer $x$, find the smallest $0$-based index $p$ such that $a_p=x$.

If no such index exists, print -1.

Input

• The first line contains integers $n$ and $x$.
• The second line contains $n$ integers $a_0,a_1,\ldots,a_{n-1}$.

Output

Print the first index of $x$, or -1 if $x$ does not occur.

Subtasks

Subtask 1 (100 points): $1\le n\le10^5$; $-10^9\le a_i,x\le10^9$.

Examples

Input

7 5
2 5 3 5 8 5 1

Output

1

Explanation

Value $5$ occurs at indices $1,3,5$. The smallest is $1$.