I found 4 colors. Given a color for A, we need two others for B and E, and since D is adjacent to A B E, we need a fourth. C can have the same color as E. --rtabchou
I found 4 colors. Given a color for A, we need two others for B and E, and since D is adjacent to A B E, we need a fourth. C can have the same color as E. --rtabchou