View Compilation Error

0_0_26218333_10737.cpp:12:12: error: "(" may not appear in macro parameter list
  #define M((L+R)>>1)
            ^
0_0_26218333_10737.cpp: In member function 'KDtree::Node* KDtree::build_tree(int, int, int)':
0_0_26218333_10737.cpp:42:14: error: 'M' was not declared in this scope
   cur = tree[M].f = deep;
              ^