I was solving the April Long problems, after solving the first three problems I got stuck at the fourth problem the Unit GCD problem (Div 2). Now, I am not asking for any hint or solution as I am aware that it is counted as cheating. I only want to know that being a beginner and this being my first Long contest (as far as I remember), is it possible to solve this problem by manipulating some basic properties and high school maths or does this problem require some really hard number theory concepts? I am not being lazy but it is better to know whether this problem is within my reach at this moment, once I know this then I can proceed to enhance my knowledge to tackle such problems in the future.

Note:- Suggestions for topics in number theory required to solve such problems is highly appreciated. Once again, I am not asking for a solution to the problem.