View Compilation Error

0_0_18525496_24668.cpp: In function 'int query(int, int, int, int)':
0_0_18525496_24668.cpp:111:12: error: 'M' was not declared in this scope
  if (ql <= M)    ret += query(lson, deep + 1);
            ^
0_0_18525496_24668.cpp:111:12: note: suggested alternative:
0_0_18525496_24668.cpp:27:28: note:   'getnum::M'
  int a , b , C = ~(1<<31), M = (1<<16)-1;
                            ^
0_0_18525496_24668.cpp:113:11: error: 'M' was not declared in this scope
  if (qr > M)    ret += query(rson, deep + 1);
           ^
0_0_18525496_24668.cpp:113:11: note: suggested alternative:
0_0_18525496_24668.cpp:27:28: note:   'getnum::M'
  int a , b , C = ~(1<<31), M = (1<<16)-1;
                            ^