View Compilation Error

0_0_16323322_3324.cpp: In function 'int main()':
0_0_16323322_3324.cpp:54:28: error: reference to 'is_same' is ambiguous
             if(is_data(s)||is_same(s)) {sum+=a;}
                            ^
0_0_16323322_3324.cpp:35:6: note: candidates are: bool is_same(std::string)
 bool is_same(string num){
      ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/move.h:57:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_pair.h:59,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_algobase.h:64,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/char_traits.h:39,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/ios:40,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/ostream:38,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:39,
                 from 0_0_16323322_3324.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/c++/type_traits:922:12: note:                 template<class, class> struct std::is_same
     struct is_same;
            ^