#region memo
/* 偶奇が大切な問題では、偶数番目と奇数番目を分けて配列に入れる
 * 文字列の処理は遅い。char[]で計算して、最後にstringにする
 */
#endregion

using System.Collections;

using System.Text;
using System.Threading.Tasks;
using static System.Math;
using static System.Console;
using System.Collections.Generic;
using System.Linq;
using System;
class Program
{
    static void Main()
    {
        while (true)
        {

            int[] data = ReadIntN();
            int n = data[0];
            int x = data[1];
            if (n == 0 && x == 0) break;

            int min = Min(n, x);
            int ans = 0;
            for (int i = 1; i <= min; i++)
            {
                for (int j = i+1; j <= min; j++)
                {
                    for (int k = j+1; k <= min; k++)
                    {
                        if (i+j+k == x)
                        {
                            ans++;
                        }
                    }
                }
            }
            Console.WriteLine(ans);
        }
        //ReadLine();


    }


    #region Reader
    static string ReadStr()
    {
        return Console.ReadLine();
    }
    static string[] ReadStrN()
    {
        return Console.ReadLine().Split(' ');
    }
    static int ReadInt()
    {
        return Convert.ToInt32(Console.ReadLine());
    }
    static int[] ReadIntN()
    {
        return Console.ReadLine().Split(' ').Select(s => Convert.ToInt32(s)).ToArray();
    }
    static long ReadLong()
    {
        return Convert.ToInt64(Console.ReadLine());
    }
    static long[] ReadLongN()
    {
        return Console.ReadLine().Split(' ').Select(s => Convert.ToInt64(s)).ToArray();
    }
    static long[,] ReadLongMatrix(int r, int c)
    {
        var mat = new long[r, c];
        for (int i = 0; i < r; ++i)
        {
            var x = ReadLongN();
            for (int j = 0; j < c; ++j)
            {
                mat[i, j] = x[j];
            }
        }
        return mat;
    }
    static Tuple<string, string>[] ReadTupleStr(int n)
    {
        List<Tuple<string, string>> list = new List<Tuple<string, string>>();
        for (int i = 0; i < n; ++i)
        {
            var ab = ReadStrN();
            list.Add(new Tuple<string, string>(ab[0], ab[1]));
        }
        return list.ToArray();
    }
    static Tuple<long, long>[] ReadTupleLong(int n)
    {
        List<Tuple<long, long>> list = new List<Tuple<long, long>>();
        for (int i = 0; i < n; ++i)
        {
            var ab = ReadLongN();
            list.Add(new Tuple<long, long>(ab[0], ab[1]));
        }
        return list.ToArray();
    }
    static Tuple<int, int>[] ReadTupleInt(int n)
    {
        List<Tuple<int, int>> list = new List<Tuple<int, int>>();
        for (int i = 0; i < n; ++i)
        {
            var ab = ReadIntN();
            list.Add(new Tuple<int, int>(ab[0], ab[1]));
        }
        return list.ToArray();
    }
    static Tuple<double, double>[] ReadTupleDouble(int n)
    {
        List<Tuple<double, double>> list = new List<Tuple<double, double>>();
        for (int i = 0; i < n; ++i)
        {
            var ab = ReadLongN();
            list.Add(new Tuple<double, double>(ab[0], ab[1]));
        }
        return list.ToArray();
    }
    static Dictionary<int, HashSet<int>> ReadAdjacencyList(int N, int M)
    {
        Dictionary<int, HashSet<int>> dict = new Dictionary<int, HashSet<int>>();
        for (int i = 0; i <= N; ++i)
        {
            dict.Add(i, new HashSet<int>());
        }
        for (int i = 0; i < M; ++i)
        {
            var ab = ReadIntN();
            dict[ab[0]].Add(ab[1]);
            dict[ab[1]].Add(ab[0]);
        }
        return dict;
    }
    #endregion

}


Measured memory_bytes: 16460