Double Rainbow

문제

Let $PP$ be a set of $nn$ points on the $xx$-axis and each of the points is colored with one of the colors $1,2,\dots ,k1,\; 2,\; \backslash dots\; ,\; k$. For each color 𝑖 of the 𝑘 colors, there is at least one point in $PP$ which is colored with $ii$. For a set $P^{\mathrm{\prime }}P\text{'}$ of consecutive points from $PP$, if both $P^{\mathrm{\prime }}P\text{'}$ and $P\mathrm{\backslash }{P}^{\mathrm{\prime }}P\; \backslash backslash\; P\text{'}$ contain at least one point of each color, then we say that $P^{\mathrm{\prime }}P\text{'}$ makes a double rainbow. See the below figure as an example. The set 𝑃 consists of ten points and each of the points is colored by one of the colors $11$, $22$, $33$, and $44$. The set $P^{\mathrm{\prime }}P\text{'}$ of the five consecutive points contained in the rectangle makes a double rainbow.

Given a set $PP$ of points and the number $kk$ of colors as input, write a program that computes and prints out the minimum size of $P^{\mathrm{\prime }}P\text{'}$ that makes a double rainbow.

입력

Your program is to read from standard input. The input starts with a line containing two integers $nn$ and $kk$ (1 ≤ k ≤ n ≤ 10,000), where $nn$ is the number of the points in $PP$ and $kk$ is the number of the colors. Each of the following $nn$ lines consists of an integer from $11$ to $kk$, inclusively, and the $ii$-th line corresponds to the color of the $ii$-th point of $PP$ from the left.

출력

Your program is to write to standard output. Print exactly one line. The line should contain the minimum size of $P^{\mathrm{\prime }}P\text{'}$ that makes a double rainbow. If there is no such $P^{\mathrm{\prime }}P\text{'}$, print 0.