delete table if exist then create table postgres

I have table yourtablename  how can Put script to delete table if it exist thwn i can create table

 CREATE TABLE yourtablename AS
SELECT sename."Date",
    sename.name,
    sename."Open",
    sename."Low",
    sename."Close",
    COALESCE(lag(sename."Open") OVER (PARTITION BY sename.name ORDER BY sename.name), sename."Open") AS lag_start,
    COALESCE((sename."Open" - lead(sename."Open") OVER (PARTITION BY sename.name ORDER BY sename."Date")), sename."Open") AS chg
   FROM sename
  ORDER BY sename.name, sename."Date" DESC;
                                  

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