Schill said France could engage a division of 20,000 troops within 30 days to operate as part of an allied coalition. Paris, he added, would be able to command a force of around 60,000 soldiers made up of French and other allied troops. The French army comprises some 121,000 soldiers, with 24,000 reservists.
Unless you're Ukraine announcing months in advance exactly where you're going to launch your big "counter-offensive" giving Russia all the time in the world to prepare defensive lines.