Type in Russia. Each successive country will be the alphabetically-first country bordering the current country that you HAVEN'T visited yet. Keep entering countries until it is impossible to continue
Start With Russia. Only land borders are used. Rivers and Canals may be crossed, but not seas and lakes. EXCLUDE extra-territorial areas such as French Guiana or Ceuta. EXAMPLE: If we were starting in the USA, the lowest alphabetical country bordering the US is Canada, so that would be the next entry (and a dead end, in this case).