var
  I,J,s1,s2,d1,d2,it1,it2,ans:integer;

begin
  it1 := 3;

  d1 := 7;
  d2 := 3;

  for I := 1 to 100 do
  begin
    it2 := 2;

    for J := 1 to 100 do
    begin
      if it2 = it1 then
        ans := ans + it1;

      it2 := it2 + d2;
    end;
    it1 := it1 + d1;
  end;

  writeln(ans);
end.