package question;

/**
 * @author Roderland
 * @since 1.0
 */
public class Question1802 {
 public static void main(String[] args) {
 System.out.println(new Question1802().maxValue(1,0,24));
 }
 public int maxValue(int n, int index, int maxSum) {
 maxSum-=n;
 int i=0;
 int j=maxSum;
 int res=0;
 while (i<=j) {
 int m=(i+j)/2;
 if (f(n, index, maxSum, m)) {
 i=m+1;
 res=m;
 } else {
 j=m-1;
 }
 }
 return res+1;
 }

 public boolean f(int n, int index, int maxSum, int x) {
 long left=Math.min(x, index);
 long right=Math.min(x, n-index-1);
 left=(2*x-left)*(left+1)/2;
 right=(2*x-right)*(right+1)/2;
 long res=left+right-x;
 return res<=maxSum;
 }
}