Task: Question Answering
Input (English): Passage: Marien Ngouabi, who had participated in the coup, assumed the presidency on December 31, 1968. One year later, President Ngouabi proclaimed Congo Africa's first "people's republic", the People's Republic of the Congo, and announced the decision of the National Revolutionary Movement to change its name to the Congolese Labour Party (PCT). Ngouabi survived an attempted coup in 1972 but was assassinated on March 16, 1977. An 11-member Military Committee of the Party (CMP) was then named to head an interim government with Joachim Yhombi-Opango to serve as President of the Republic. Two years later, Yhombi-Opango was forced from power and Denis Sassou Nguesso become the new president. Question: Who became president of the Congo in 1968?
Output (English): Marien Ngouabi