#include <bits/stdc++.h>
int main() {
  int i, j, k;
  int n, x;
  int count;
  while (1) {
    scanf("%d %d ", &n, &x);
    if (n == 0 && x == 0) break;
    count = 0;
    for (i = 1; 3 * i + 3 <= x; i++) {
      for (j = i + 1; i + 2 * j + 1 <= x; j++) {
        for (k = n; k > j; k--) {
          if (x == i + j + k) {
            count++;
            break;
          } else if (x >= i + j + k) {
            break;
          }
        }
      }
    }
    printf("%d\n", count);
  }
  return 0;
}
