/in/foo.cc: In function 'void build(long long unsigned int, long long unsigned int, long long unsigned int)':
/in/foo.cc:29:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid=l+r>>1;
          ~^~
/in/foo.cc: In function 'void chan(long long unsigned int, long long unsigned int, long long unsigned int)':
/in/foo.cc:41:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid=ln+rn>>1;
          ~~^~~