context: During the Democratic Kampuchea days, the 68,000-member Khmer Rouge-dominated CPNLAF  force, which completed its conquest of Phnom Penh, Cambodia in April 1975, was renamed the RAK . This name dated back to the peasant uprising that broke out in the Samlot district of Battambang Province in 1967. Under its long-time commander and then Minister of Defense Son Sen, the RAK had 230 battalions in 35 to 40 regiments and in 12 to 14 brigades. The command structure in units was based on three-person committees in which the political commissar ranked higher than the military commander and his deputy. Cambodia was divided into zones and special sectors by the RAK, the boundaries of which changed slightly over the years. Within these areas, the RAK's first task was the peremptory execution of former Khmer National Armed Forces  officers and of their families, without trial or fanfare to eliminate KR enemies. The RAK's next priority was to consolidate into a national army the separate forces that were operating more or less autonomously in the various zones. The Khmer Rouge units were commanded by zonal secretaries who were simultaneously party and military officers, some of whom were said to have manifested "warlord characteristics". Troops from one zone frequently were sent to another zone to enforce discipline. These efforts to discipline zonal secretaries and their dissident or ideologically impure cadres gave rise to the purges that were to decimate RAK ranks, to undermine the morale of the victorious army, and to generate the seeds of rebellion. In this way, the KR used the RAK to sustain and fuel its violent campaign.
question: What two ranks were secondary to the political commissar?
answer: military commander and his deputy