How many years after the Russians were expelled from Tehran did the British General Ironside promote Reza Khan to lead an entire brigade?
return the  Russians were expelled from  Tehran ;return the  British General Ironside promotes Reza Khan to lead an entire brigade ;return year of #1 ;return year of #2 ;return the  difference of #4 and  #3
['select', 'select', 'project', 'project', 'arithmetic']