2 pieces 10

B 8 C

European development fund

Then remove the redundant letters according to the topic, and there will be B=A+4, C=0, D=A-6, E = 16-a, and F = A+2. When we go back to the Rubik's Cube, we will find that the vertical column in the middle is A 8 16-A, then we know that the sum needed by the Rubik's Cube is 24.

2 12 10

16 8 0

6 4 14