[Boost-users] [counting_range] why?

Ok, maybe I'm having a senior moment here, but why is the second line wrong? Thx, Rob. #include <boost/range/counting_range.hpp> int main( ) { // Ok auto r = boost::counting_range( 0, 3 ); // Not Ok. auto s = boost::counting_range<int>( 0, 3 ); }