uses crt;
var i,n:intger;
begin
write('nhap 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 la so nguyen to');
end;
readln
end.