foo.cc: In function 'int main()':
foo.cc:11:8: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   11 |   mid=l+r>>1;
      |       ~^~
foo.cc:7:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    7 |  scanf("%lld",&n);
      |  ~~~~~^~~~~~~~~~~

Found 10 testcases.
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