"For a small country like Ukraine ..."For a small country like Ukraine, the primary concern should be, "who is our biggest security threat and how do we avoid it". Money is secondary if your country will not exist.
Ukraine's smaller than Russia, of course, but Ukraine's hardly a 'small country' by European or world standards.
Ukraine has the second largest land area and seventh largest population of all countries in Europe.
In order of population:
1) Russia 2) Germany 3) UK 4) France 5) Italy 6) Spain (slightly more than Ukraine) 7) Ukraine 8) Poland