program SNT;
uses crt;
var n,i: integer;
Begin
clrscr;
write('Nhap n: '); readln(n);
if n<=1 then write('n khong la so nguyen to')
else
begin
i:=2;
while n mod i<>0 do i:=i+1;
if i=n then write(n,' la so nguyen to')
else write(n,' khong la so nguyen to');
end;
readln
End.