I want to create a makro in Excel which performs - after pressing a button - the below. I attached some dummy data that is formatted like the actual sheet.

There are several data blocks that are seperated by headlines in Sheet 1. From these headlines, I want to get a string of numbers and put it into column S for each line with data below that heading. In line 6 the heading says "2000", thus lines 8-19 should have a "2000" in column S and so on. The number I want to get is always after the word "Monthlyaccount" but the lenght of the number can be different - from 1 to 7 digits. For lines where no data is given (data lines might be recognized by looking if in A is a valid date given) there should just be "ERR" instead of the number.
Can anyone help out?
Thanks so much upfront!