var startYear = 2018;
var endYear = 2019;
print(countries)
for(var i=0;i<countries.size().getInfo();i++){
  var startMonth =countries.filter(ee.Filter.eq('startMonth',i));
  for(var j=0;j<countries.size().getInfo();j++){
    var startDay = countries.filter(ee.Filter.eq('startDay',j));
    var start = ee.Date.fromYMD(startYear, startMonth,startDay);

  }
}
for(var i=0;i<countries.size().getInfo();i++){
  var endMonth =countries.filter(ee.Filter.eq('endMonth',i));
  for(var j=0;j<countries.size().getInfo();j++){
    var endDay = countries.filter(ee.Filter.eq('endDay',j));
    var end  = ee.Date.fromYMD(endYear, endMonth, endDay);
    //print(typeof endMonth)
  }
}
print(typeof startDay)
print(start)
print(end)