Coarse whole wheat flour

Hi - new to the site and to bread baking and wondering where to get coarse whole wheat flour.  I've found a very UN-intimidating recipe for a baguette that calls for 1-1/2 c. white flour, 1-1/2 c. whole wheat flour and 3/4 c. coarse ground whole wheat flour.  It does say that if you can't find the coarse ground, just use more regular whole wheat flour.  But I'm wondering if it's worth tracking down the coarse ground and where to find it.  My grocery store is pretty good, but they didn't have it.  Thanks for any help and advice!