trim (JustS lx) NothingS   t = greater lx t where greater lo (Bin _ x _ r) | x <= lo = greater lo r
                                                  greater _  t' = t'
trim (JustS lx) NothingS   t = greater lx t where greater lo (Bin _ x _ r) | x <= lo = greater lo r
                                                  greater _  t' = t'
trim (JustS lx) NothingS   t = greater lx t where greater lo (Bin _ x _ r) | x <= lo = greater lo r
                                                  greater _  t' = t'