from sys import stdin

T = int(stdin.readline())
for t in range(T):
  stdin.readline()
  A, B, C, D = [ int(x) for x in stdin.readline().split() ]

  cube = [A,B,C]
  cube.sort()
  if D <= cube[2] - cube[1]:
    cube[2] -= D
  else:
    D -= cube[2] - cube[1]
    cube[2] = cube[1]
    if D <= 2 * (cube[1] - cube[0]):
      cube[1] -= (D+1)/2
      cube[2] -= (D+0)/2
    else:
      D -= 2 * (cube[1] - cube[0])
      cube[1] = cube[2] = cube[0]
      cube[0] -= (D+2)/3
      cube[1] -= (D+1)/3
      cube[2] -= (D+0)/3
  print cube[0] * cube[1] * cube[2]