 Complete the following phrase:  In 1950, Tribhuvan went into exile at the Indian Embassy in a campaign aimed at removing the Ranas from power, in response Gyanendra, grandson of Tribhuvan was named the new king of Nepal by the Rana government. Tribhuvan returned to Nepal after a mutual agreement between Ranas which ended the Ranas rule and was crowned the king again in 1951. Upon Tribhuvans death, Mahendra became king in 1955. In 1960, he began the party-less political system, Panchayat. During a hunting event, he suffered a heart attack, and his son Birendra assumed the throne in 1975, two years after his fathers death. In 1990, pro-democracy riots broke out in Nepal, resulting in the country becoming a constitutional monarchy. On 1 June 2001, the 