453899 program to find google ads on websites

This project is to make a clone of the program "Adwords Digger". It's a small, lightweight program with just one function. The way it works is: I type in a list of keywords into a box. (eg, 20 to 100 keywords). Click "Go". Each keyword is put into Google search one at a time. Visit each URL in the top 20 search results for that keyword. Check if each URL page has a Google Ad on it. If so, save that keyword and URL in a list. (eg csv or txt file) Continue until all keywords have been searched. It needs to work without getting an error from Google - if you use a script that inserts all the keywords at once into Google search bar, Google will block it and say that "it seems you are using automated search queries" or something similar. Perhaps use random proxies and random time delays for each search.