while true
  n,x = gets.split(" ").map(&:to_i)
  if (n==0&&x==0) then
    break
  end
end
    
count = 0
for i in 1..n
  
  for j in 1..n
    if i != j then
      break
    end
    
    for k in 1..n
      if k != j then
        break
      end
      if(x == i+j+k) then
        count+=1
      end
    end
  end
end
p count