CF570B.Simple Game

One day Misha and Andrew were playing a very simple game. First, each player chooses an integer in the range from $1$ to $n$ . Let's assume that Misha chose number $m$ , and Andrew chose number $a$ .

Then, by using a random generator they choose a random integer $c$ in the range between $1$ and $n$ (any integer from $1$ to $n$ is chosen with the same probability), after which the winner is the player, whose number was closer to $c$ . The boys agreed that if $m$ and $a$ are located on the same distance from $c$ , Misha wins.

Andrew wants to win very much, so he asks you to help him. You know the number selected by Misha, and number $n$ . You need to determine which value of $a$ Andrew must choose, so that the probability of his victory is the highest possible.

More formally, you need to find such integer $a$ ( $1<=a<=n$ ), that the probability that is maximal, where $c$ is the equiprobably chosen integer from $1$ to $n$ (inclusive).

The first line contains two integers $n$ and $m$ ( $1<=m<=n<=10^{9}$ ) — the range of numbers in the game, and the number selected by Misha respectively.

Print a single number — such value $a$ , that probability that Andrew wins is the highest. If there are multiple such values, print the minimum of them.

In the first sample test: Andrew wins if $c$ is equal to $2$ or $3$ . The probability that Andrew wins is $2/3$ . If Andrew chooses $a=3$ , the probability of winning will be $1/3$ . If $a=1$ , the probability of winning is $0$ .

In the second sample test: Andrew wins if $c$ is equal to $1$ and $2$ . The probability that Andrew wins is $1/2$ . For other choices of $a$ the probability of winning is less.