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