savrsen.cpp:32:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main ()
       ^
savrsen.cpp: In function 'int main()':
savrsen.cpp:39:54: error: no matching function for call to 'max(long long int, int)'
   ans += i * ((b / i - 1) - max (((a - 1) / i - 1), 0));
                                                      ^
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 savrsen.cpp:1:
/usr/include/c++/7/bits/stl_algobase.h:219:5: note: candidate: template<class _Tp> constexpr 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:
savrsen.cpp:39:54: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   ans += i * ((b / i - 1) - max (((a - 1) / i - 1), 0));
                                                      ^
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 savrsen.cpp:1:
/usr/include/c++/7/bits/stl_algobase.h:265:5: note: candidate: template<class _Tp, class _Compare> constexpr 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:
savrsen.cpp:39:54: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   ans += i * ((b / i - 1) - max (((a - 1) / i - 1), 0));
                                                      ^
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 savrsen.cpp:1:
/usr/include/c++/7/bits/stl_algo.h:3462:5: note: candidate: template<class _Tp> constexpr _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:
savrsen.cpp:39:54: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   ans += i * ((b / i - 1) - max (((a - 1) / i - 1), 0));
                                                      ^
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 savrsen.cpp:1:
/usr/include/c++/7/bits/stl_algo.h:3468:5: note: candidate: template<class _Tp, class _Compare> constexpr _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:
savrsen.cpp:39:54: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   ans += i * ((b / i - 1) - max (((a - 1) / i - 1), 0));
                                                      ^