如何从Google sheets中的单元格中获取值,用作Google脚本中的数字变量

A3是a=COUNTA(B2:VF2)-1,当前计算结果为446

function RangeCopyToLog() {
  var spreadsheet = SpreadsheetApp.getActive();
  var destSheet = spreadsheet.getSheetByName("Xp Log");
  var lastRow = destSheet.getLastRow();
  var copyColEnd = destSheet.getRange('A3') + 1 //Problem is here
  destSheet.insertRows(lastRow + 1,1);
  destSheet.getRange(1,3,1,copyColEnd).copyTo(destSheet.getRange(34,3,1,copyColEnd), SpreadsheetApp.CopyPasteType.PASTE_VALUES, false);
 // destSheet.getRange('D1:D30').copyTo(destSheet.getRange(lastRow + 1,1), SpreadsheetApp.CopyPasteType.PASTE_NORMAL, true);
 // destSheet.getRange('D1:D30').clearContent();
};