def up_to(last): return range(last+1)

def has_no_repeats(square):
  for i in up_to(15):
    for j in up_to(i-1):
      if square[i]==square[j]: return 0 # i.e., there *is* a repeat.
  return 1  # we finished without finding a repeat. Hooray!

a,b,c,d = 10,2,20,00

for m in up_to(b+c):
  p = b+c-m
  for g in up_to(a+p):
    j = a+p-g
    for f in up_to(d+m):
      k = d+m-f
      n = g+k-b
      if n<0: continue
      o = f+j-c
      if o<0: continue
      for h in up_to(a+m):
        l = a+m-h
        e = j+k-h
        i = f+g-l
        if e<0 or i<0: continue
        if has_no_repeats([a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p]):
          print a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p