At the beginning of 1664, the Imperial Army was divided into three corps: In the south, 17,000 Hungarian-Croatian troops under the command of Nikola Zrinski. In the center, the main army of Montecuccoli, which was 28,500 men strong, and in the north some 8,500 men under General Jean-Louis Raduit de Souches. There were some 12,500 men in reserve to defend the fortresses. This army of 66,500 men was not united, as the differences of opinion between the commanders were very strong, especially with Zrinski. As a preparation for campaigns planned for 1664, Zrinski set out to destroy the strongly fortified Ottoman bridge  bridge) which, since 1566, had linked Darda  to Osijek across the Drava and the marshes of Baranya. Destruction of the bridge would cut off the retreat of the Ottoman Army and make any Turkish reinforcement impossible for several months. Re-capturing strong fortresses  on his way, Zrinski advanced 240 kilometers on enemy territory and destroyed the bridge on February 1, 1664. He didn't succeed in conquering Nagykanizsa, the main objective. The siege had to be lifted when in June the main army of Köprülü approached. The Turks besieged and conquered Zrinski's stronghold Novi Zrin, which had to be abandoned when Montecuccoli refused to come to its rescue. Zrinski would never forgive this, which would eventually lead to the Magnate conspiracy  in Croatia, and "Wesselényi conspiracy"  in Hungary).
Question: How many fewer troops did General Jean-Louis Raduit de Souches have than Montecuccoli ?
Answer: 20000