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]
  while D:
    cube.sort()
    cube[2] -= 1
    D -= 1
  print cube[0] * cube[1] * cube[2]