SQL & PL/SQL

I am importing data from csv files and storing as imp_nats on daily basis, I have current table nats which has data...

What i am trying to do is to compare count from both the table and if difference is less than equal to 1% then replacing current nats table by imp_nats...

 create or replace
PROCEDURE SP_IMPORTNATS
as
V_NATS number(20):=0,
V_IMP_NATS number(20):=0,
V_CNT_NATS number(20):=0,

BEGIN
   
   begin
      SELECT COUNT(*) INTO v_NATS  FROM NATS ;
 
       select count(*) INTO v_IMP_NATS  FROM IMP_NATS ;
          
      v_CNT_NATS := round(((v_NATS - v_IMP_NATS) * 100) / v_NATS) ;
     
 IF (V_CNT_NATS =1)  or (V_CNT_NATS = 0) or (V_CNT_NATS = -1) then
begin
 execute immediate 'drop table NATS_BK';
execute immediate 'alter table NATS rename to NATS_BK';
EXECUTE IMMEDIATE 'alter table IMP_NATS rename to NATS';
end;
end if;

   end;
end; 

When i am trying compile its giving me error please help...