It's inadvisable generally to take four A-levels where two aren't A-level Maths and A-level Further Maths, because it's a signifcant step up in workload and there is no benefit to it. This is especially true if you are already taking two languages, which is an enormous workload in of itself. Universities make offers on the basis of three A-levels; doing extra A-levels will not score you "bonus points" when applying. Univeristies (especially e.g. Oxbridge, LSE, UCL etc) would much prefer to see you do very well in three subjects than less well in four.
As such you may want to consider A-level Further Maths in place of Politics or (preferably) one of the languages. Several of the "top" economics courses (e.g. LSE and Cambridge) normally expect applicants who have it available to them to take, and for LSE specifically something like 85% of successful applicants have taken FM. Bear in mind language A-levels have a large on-going workload, as does maths. You will be extremely busy throughout the course with two languages and maths; it might be better to stick to only one language.
Additionally, you should be aware that most universities teach Russian from scratch, and in fact some universities can't accommodate students wanting to do further language study in Russian if they have a background in the subject. I would recommend dropping Russian, and either sticking with those three, or taking up Further Maths as a fourth, to maintain a more useful and balanced combination of subjects both in terms of entry criteria and for once you are on your prospective degree course, as well as to actually maximise your ability to do as well as possible in the A-levels of themselves.