SELECT Country FROM perpetrator WHERE Injured  >  50 INTERSECT SELECT Country FROM perpetrator WHERE Injured  <  20
Show the countries that have both perpetrators with injures more than 50 and perpetrators with injures smaller than 20.
[Schema (values) (types)]: | perpetrator |  perpetrator : perpetrator_id (text) , people_id (number) , date (number) , year (text) , location (number) , country (text) , killed (text) , injured (number) | people : people_id (text) , name (number) , height (number) , weight (text) , home town (number);