In file included from /nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/istream:39,
                 from /nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/sstream:38,
                 from /nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/complex:45,
                 from /nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/ccomplex:39,
                 from stdc++.h:54:
In member function 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long long int) [with _CharT = char; _Traits = std::char_traits<char>]',
    inlined from 'int main()' at foo.cc:22:10:
/nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/ostream:202:25: warning: 'ans' may be used uninitialized [-Wmaybe-uninitialized]
  202 |       { return _M_insert(__n); }
      |                ~~~~~~~~~^~~~~
foo.cc: In function 'int main()':
foo.cc:12:38: note: 'ans' was declared here
   12 |                 ll l=1,r=(m+1)/2,mid,ans;//保证pi≤qi
      |                                      ^~~

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