import java.util.ArrayList;
import java.util.Scanner;
public class HowManyWays {
private static Scanner sc = new Scanner(System.in);
private static ArrayList<Integer> result = new ArrayList<Integer>();
public static void main(String[] args) {
while(sc.hasNextLine()){
//入力を受け取る
int maxNumber= sc.nextInt();
int sum = sc.nextInt();
if(maxNumber == 0 && sum == 0){
break;
}
//求めた合計と和が同じ値になる3つの数の組み合わせを求め
//結果リストに追加する
setNumCombinations(maxNumber, sum);
}
//結果を出力する
printAllNumCombinations();
}
private static int findCombinations(int maxNumber, int sum){
int numCombinations = 0;
for(int i = 1; i < maxNumber - 1; i++){
for(int j = i + 1; j < maxNumber; j++){
for(int k = j + 1; k < maxNumber + 1; k++){
if(isSame(i, j, k, sum)){
numCombinations++;
}
}
}
}
return numCombinations;
}
private static boolean isSame(int a, int b, int c, int sum){
if(sum == a + b + c){
return true;
}
else{
return false;
}
}
private static void setNumCombinations(int maxNumber, int sum){
result.add(findCombinations(maxNumber, sum));
}
private static void printNumCombinations(int i){
System.out.println(result.get(i));
}
private static void printAllNumCombinations(){
for(int i = 0; i < result.size(); i++){
printNumCombinations(i);
}
}
}