jnl (Just (x', lv')) (x, lv) = if x' < x then Just (x', lv') else Just (x, lv)
jnl (Just (x', lv')) (x, lv) = if x' < x then Just (x', lv') else Just (x, lv)
jnl (Just (x', lv')) (x, lv) = if x' < x then Just (x', lv') else Just (x, lv)