function dodajWydarzenia()
{
  var ss = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
  var lr = ss.getLastRow();
  var data = ss.getRange("A2:D" + lr).getValues();
  var cal = CalendarApp.getCalendarById("5ta8ltc1uqa3ij74t5qa8g48fk@group.calendar.google.com");
  var fromDate = new Date(2019,0,1,0,0,0);
  var toDate = new Date(2030,0,1,0,0,0);
  var events = cal.getEvents(fromDate, toDate);

  for(var i=0; i<events.length;i++)
  {
    var ev = events[i];
    ev.deleteEvent();
  }

  for(var i = 0;i<data.length;i++)
      {
        cal.createAllDayEvent(data[i][0], new Date(data[i][1]), {location:data[i][2], description:data[i][3]});
      }
}