<human>:  What is the difference between a prime minister and a president?
<bot>: The main difference between a prime minister and a president is that a prime minister is the head of the government in a parliamentary system, while a president is the head of government in a presidential system. In a parliamentary system, the prime minister is appointed by the legislative body, while a president is directly elected by the people. The role of the prime minister is to manage the legislative agenda in parliament and to lead the government, while the role of the president is to serve as the head of state and to lead the executive branch of government.