How many days passed from the arrival of Army Group South until the Soviet counterattack on the 1st Panzer Group?
return the  arrival of Army Group  South ;return the  Soviet counterattack on the   1st Panzer Group  ;return when  was  #1 ;return when  was  #2 ;return difference of #3 and  #4 in  days
['select', 'select', 'project', 'project', 'arithmetic']