/in/foo.cc: In function 'void build(int, int, int)':
/in/foo.cc:23:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid=l+r>>1;
          ~^~
/in/foo.cc: In function 'int ask(int, int, int)':
/in/foo.cc:37:16: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid=t[p].l+t[p].r>>1;
          ~~~~~~^~~~~~~
/in/foo.cc: In function 'void upd(int, int, int, int)':
/in/foo.cc:46:16: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid=t[p].l+t[p].r>>1;
          ~~~~~~^~~~~~~