declare
a int;
x int;
divcount int;
begin
a:=:a;
divcount:=0;
for x in 1..a
loop
if (mod(a,x)=0) then
divcount:=divcount+1;
end if;
end loop;
if(divcount=2) then
dbms_output.put_line('true');
else
dbms_output.put_line('false');
end if;
end;
/