/in/foo.cc:3:1: error: '_int128' does not name a type
 _int128 x,y;
 ^~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:5:7: error: 'x' was not declared in this scope
  cin>>x>>y;
       ^
/in/foo.cc:5:10: error: 'y' was not declared in this scope
  cin>>x>>y;
          ^