+ int material = 67 * (pos.count<PAWN>(stm) - pos.count<PAWN>(~stm))
+ + 395 * (pos.count<KNIGHT>(stm) - pos.count<KNIGHT>(~stm))
+ + 288 * (pos.count<BISHOP>(stm) - pos.count<BISHOP>(~stm))
+ + 630 * (pos.count<ROOK>(stm) - pos.count<ROOK>(~stm))
+ + 857 * (pos.count<QUEEN>(stm) - pos.count<QUEEN>(~stm));
+