var n, i: integer;
begin
clrscr;
write('Nhap so N = '); readln(N);
if N <= 1 then writeln(N,' khong phai so nguyen to')
else
begin
i:= 2;
while (n mod i<>0) do i:= i + 1;
if i = N then writeln(N,' la so nguyen to')
else writeln(N,' khong phai so nguyen to');
end;
readln
end.
