View Compilation Error

0_0_35630455_4219.cpp: In function 'int main()':
0_0_35630455_4219.cpp:9:14: error: missing template arguments before 'AA'
     std::set AA, BB;
              ^
0_0_35630455_4219.cpp:13:13: error: 'AA' was not declared in this scope
             AA.insert (A); AA.insert (B);
             ^
0_0_35630455_4219.cpp:14:13: error: 'BB' was not declared in this scope
             BB.insert (B);
             ^
0_0_35630455_4219.cpp:16:13: error: 'AA' was not declared in this scope
         if (AA - BB == 1) {
             ^
0_0_35630455_4219.cpp:16:18: error: 'BB' was not declared in this scope
         if (AA - BB == 1) {
                  ^
0_0_35630455_4219.cpp:21:9: error: 'AA' was not declared in this scope
         AA.clear (); BB.clear ();
         ^
0_0_35630455_4219.cpp:21:22: error: 'BB' was not declared in this scope
         AA.clear (); BB.clear ();
                      ^