Task: Question Answering
Input (English): Passage: St Denys' Church, Sleaford, is a medieval Anglican parish church in Sleaford, Lincolnshire, England. While a church and a priest have probably been present in the settlement since approximately 1086, the oldest parts of the present building are the tower and spire, which date to the late 12th and early 13th centuries; the stone broach spire is one of the earliest examples of its kind in England. The Decorated Gothic nave, aisles and north transept were built in the 14th century. The church was altered in the 19th century: the north aisle was rebuilt by the local builders Kirk and Parry in 1853 and the tower and spire were largely rebuilt in 1884 after being struck by lightning. St Denys' remains in use for worship by the Church of England.
The church is a Grade I listed building, a national designation given to "buildings of exceptional interest". It is a prime example of Decorated Gothic church architecture in England, with the architectural historians Sir Nikolaus Pevsner and John Harris noting that "it is a prolonged delight to follow the mason's inventiveness". The church's tracery has attracted special praise, with Simon Jenkins arguing that its Decorated windows are "works of infinite complexity". Built out of Ancaster stone with a lead roof, St Denys' is furnished with a medieval rood screen and a communion rail, possibly by Sir Christopher Wren, and has a peal of eight bells, dating to 1796. The church also houses several memorials, including two altar tombs commemorating members of the Carre family, Sleaford's lords of the manor in the 17th century. 
Question: What kind of building is St Denys'?
Output (English): Church.