solution.java

import java.io.*;
import java.math.*;
import java.text.*;
import java.util.*;
import java.util.regex.*;

public class solution {

    /*
     * Complete the pageCount function below.
     */
    static int pageCount(int n, int p) {
        /*
         * Write your code here.
         */
        // it will take p/2 turns to reach the pth page from front
        // and (n-p)/2 pages from the back. Take the minimum out of the two
        int ans = Math.min(p / 2, n / 2 - p / 2);
        return ans;
    }

    private static final Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) throws IOException {
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int n = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])*");

        int p = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])*");

        int result = pageCount(n, p);

        bufferedWriter.write(String.valueOf(result));
        bufferedWriter.newLine();

        bufferedWriter.close();

        scanner.close();
    }
}