foo.cc: In member function 'void tree::build(int, int, int)':
foo.cc:19:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   19 |         int mid = L + R >> 1;
      |                   ~~^~~
foo.cc: In member function 'void tree::modify(int, int, int, int)':
foo.cc:29:27: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   29 |         int mid = nd[p].L + nd[p].R >> 1;
      |                   ~~~~~~~~^~~~~~~~~
foo.cc: In member function 'void tree::query(int, int)':
foo.cc:42:27: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   42 |         int mid = nd[p].L + nd[p].R >> 1;
      |                   ~~~~~~~~^~~~~~~~~

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