Mikoyan-Gurevich MiG-19, Hungarian and Romanian users

The Mikoyan-Gurevich MiG-19 was the first supersonic fighter in the world. The "P" variant was equipped with the RP-1 Izumrud radar in the nose and was armed with two 23 mm NR-23 (with some revised versions having them replaced by the 30 mm NR-30) placed in the wings. It could carry some unguided missiles in hardpoints at  the wings and, in further modifications, it could carry also K-13 air-to-air missiles.
The PM variant was not armed with cannons at all, but it was armed with four Kaliningrad K-5M beam-riding air-to-air missiles, making it a pure interceptor.
These two variants were employed by both Hungary and Romania:

• Hungary: The Air Force of the Hungarian People's Army operated 12 MiG-19PM fighters. The first 12 pilots for these aircraft started their conversion training in the USSR in July 1959. In March 1960 six aircraft were delivered with the other six being delivered in April. They were assigned to the 3rd Squadron of the 31st Fighter Regiment based at Taszár Air Base, in Hungary.
  They served until 1974 when the last MiG-19PM was written off and the surviving aircraft were placed into reserve at a disposal dump site where they received fake four digit serials matching the years they were put into storage. Therefore it wasn't uncommon to see various aircraft sharing the same serial number. 
• Romania: In 1959 the Air Force of the People's Republic of Romania received 10 MiG-19P and 45 MiG-19PMs and five more MiG-19P arrived one year later. They were assigned to the 66th Fighter Division which was tasked with the aerial defence of Bucharest.
  Initially they were based at Caracal-Deveselul Air Base but in the early 1960s they were moved to Borcea Air Base (which is still active nowadays) with a detachment assigned to Giarmata Air Base, near Timisoara, in Transylvania. Due to security reasons the fighters were re-serialised twice through their career. They were phased out in the early 1970s, although some reports claim they served a little bit longer, until the mid 1970s.
  There have also been false reports about Romanian MiG-19S fighters, but they were proven wrong.

Sources:

1. https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-19#Variants

2. Midland Publishing - Mikoyan-Gurevich MiG-19. The Soviet Union's First Production Supersonic Fighter

3. Salamander Books - The Complete Book of Fighters