for Y in C:
  pm=Y[0]+Y[1]
  px=Y[-2]+Y[-1]
  o=[k for k in range(3) if k!=i]
  for j,(jl,jr) in enumerate(I):
   for tv in range(px-jr,pm-jl+1):
    t=tv%p
    B=allow(Y,t,I[o[0]])
    if not B:continue
    D=allow(Y,t,I[o[1]])
    if not D:continue
    for b in B:
     for c in D:
      if inV((b+c)%p,t):
       S=set(Y)
       S.add(b)
       S.add(c)
       if len(S)==50 and t not in S:
        print('FOUND',i,len(Y),j,t,b,c,Y[0],Y[-1],flush=True)
        raise SystemExit
print('done')