Task: Question Answering
Input (English): Passage: The fourth Chinese domination was a period of the history of Vietnam, from 1407 to 1427 during which the country was invaded and ruled by the Chinese Ming dynasty. It was the result of the conquest of the region in 1406 to 1407. The previous periods of Chinese rules, collectively known as the Bắc thuộc periods in Vietnam, were longer-lasting, constituting much of Vietnam's history from 111 BC to 939 AD. The fourth Chinese occupation of Vietnam was eventually ended with the establishment of the Lê dynasty. 
Question: How many years did the fourth Chinese domination last in Vietnam? 
Answer type: Number 
Output (English): 20.