how to get the newest value of column E and display the value in A1 with google app script

I have never used google app script and I need help to make google spread sheet like this.You can input values in column E, and the value of the newest input is displayed in A1.

I tried below coding but it didn't work.

function myFunction() {  var spreadsheet = SpreadsheetApp.getActiveSpreadsheet();  var sheet = spreadsheet.getActiveSheet();  var range = sheet.getRange("E:E");  var inputinE = range;  var colA = sheet.getRange(1, 1);  colA = inputinE.getValues();}myFunction();