Task: Text Categorization
Input (English): Text:  Huangpu class gunboat were gunboats of the People's Republic of China's People's Liberation Army Navy. These boats were designated as Type 53A (53 Jia Xing 53甲型). They entered service in the 1950s and had been completely taken out of active service by the early 2000s and were transferred to law enforcement agencies.
Output (English): 6