foo.cc: In function 'int main()':
foo.cc:24:27: error: no matching function for call to 'max(long long int, int)'
  cout << max(a + b + c, -1);
                           ^
In file included from /usr/include/c++/7/bits/char_traits.h:39:0,
                 from /usr/include/c++/7/ios:40,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from foo.cc:1:
/usr/include/c++/7/bits/stl_algobase.h:219:5: note: candidate: template<class _Tp> const _Tp& std::max(const _Tp&, const _Tp&)
     max(const _Tp& __a, const _Tp& __b)
     ^~~
/usr/include/c++/7/bits/stl_algobase.h:219:5: note:   template argument deduction/substitution failed:
foo.cc:24:27: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
  cout << max(a + b + c, -1);
                           ^
In file included from /usr/include/c++/7/bits/char_traits.h:39:0,
                 from /usr/include/c++/7/ios:40,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from foo.cc:1:
/usr/include/c++/7/bits/stl_algobase.h:265:5: note: candidate: template<class _Tp, class _Compare> const _Tp& std::max(const _Tp&, const _Tp&, _Compare)
     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
     ^~~
/usr/include/c++/7/bits/stl_algobase.h:265:5: note:   template argument deduction/substitution failed:
foo.cc:24:27: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
  cout << max(a + b + c, -1);
                           ^
In file included from /usr/include/c++/7/algorithm:62:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:65,
                 from foo.cc:1:
/usr/include/c++/7/bits/stl_algo.h:3462:5: note: candidate: template<class _Tp> _Tp std::max(std::initializer_list<_Tp>)
     max(initializer_list<_Tp> __l)
     ^~~
/usr/include/c++/7/bits/stl_algo.h:3462:5: note:   template argument deduction/substitution failed:
foo.cc:24:27: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
  cout << max(a + b + c, -1);
                           ^
In file included from /usr/include/c++/7/algorithm:62:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:65,
                 from foo.cc:1:
/usr/include/c++/7/bits/stl_algo.h:3468:5: note: candidate: template<class _Tp, class _Compare> _Tp std::max(std::initializer_list<_Tp>, _Compare)
     max(initializer_list<_Tp> __l, _Compare __comp)
     ^~~
/usr/include/c++/7/bits/stl_algo.h:3468:5: note:   template argument deduction/substitution failed:
foo.cc:24:27: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
  cout << max(a + b + c, -1);
                           ^