def allow(Y,t,s):
 yl=Y[0]
 yu=Y[-1]
 R=set()
 for l,r in I:
  a=(l+t)%p
  b=(r+t)%p
  if a<=b:
   q=[(a-yu,b-yl)]
  else:
   q=[(a-yu,p-1-yl),(-yl,b-yu)]
  for lo,hi in q:
   lo=max(lo,s[0])
   hi=min(hi,s[1])
   if lo<=hi:
    R.update(range(lo,hi+1))
 return R