{
   ofstream outp;
   outp.open("result.txt");

   ifstream inp;
   inp.open("file0.txt");

   double xo=0, yo=0, x=0,y=0;

   while (inp >> x >> y) {
      if (x==xo) {
         yo = yo+y;
      } else {
        outp << xo << " " << yo << endl;
        xo = x;
        yo = y;
      }
   }
   outp << xo << " " << yo << endl;
   inp.close();
   outp.close();
}