Số nguyên tố - Lê Quang Tuấn

program songuyento;
uses crt;
var kt:boolean;
    so,i,x:integer;
begin
     clrscr;
     write('Nhap vao mot so bat ki: '); readln(so);
     kt:=true;
     if so>=2 then
     begin
      for i:=2 to so-1 do
          begin
          if so mod i = 0 then kt:=false;
          end;
          if kt=true then writeln('La so nguyen to!') else writeln('Khong phai so nguyen to!');
     end
     else writeln('Khong phai so nguyen to!');
     readln
end.