Here's a map, which I found here:
Your challenge is to four-color this map while minimizing your use of the fourth color.
More specifically, color the map with four colors so each region is a different color from all of its neighboring regions. Your score is the number of regions colored in your least-used color.
For instance, if you colored the map red, blue, green, and yellow, using red 30 times, blue 28 times, green 26 times, and yellow 28 times, your score would be 26.
The lowest score wins. Proofs that it is impossible to achieve a smaller score are also welcome.
I have achieved a score of
and I believe that is the lowest possible score, but feel free to try to outdo me.