Question: ÷ (pronounced "divide"), is the third studio album by English singer-songwriter Ed Sheeran, which lead single was released as a digital download on 6 January 2017 as one of the double lead singles from his third studio album "÷" (2017)?

Context paragraphs:
Nancy Mulligan (song): "Nancy Mulligan" is a song by English singer-songwriter Ed Sheeran.  It was included on the deluxe edition of his third studio album "÷" (2017).  After the album's release it charted at number 13 on the UK Singles Chart, despite not being an official single.  Sheeran recorded the song together with Beoga.

Perfect (Ed Sheeran song): "Perfect" is a song by English singer-songwriter Ed Sheeran.  It was included on his third studio album "÷" (2017).  After the album's release it charted at number 4 on the UK Singles Chart, despite not being an official single at the time.  On 21 August 2017, "Billboard" announced that "Perfect" will be the fourth single from the album.  The song impacted pop radio on 26 September 2017, as the third single from the album in the United States (fourth overall).

Happier (Ed Sheeran song): "Happier" is a song by English singer-songwriter Ed Sheeran.  It was included on his third studio album "÷" (2017).  After the album's release it charted at number 6 on the UK Singles Chart, despite not being an official single.

Shape of You: "Shape of You" is a song by English singer-songwriter Ed Sheeran.  It was released as a digital download on 6 January 2017 as one of the double lead singles from his third studio album "÷" (2017), along with "Castle on the Hill".

÷ Tour: The ÷ Tour (pronounced "divide tour") is the third world concert tour by English singer-songwriter, Ed Sheeran, in support of his third studio album, "÷" (pronounced "divide").  It officially began on March 16, 2017, in Turin, Italy.  Ticket sales started on February 2, 2017.

Castle on the Hill (song): "Castle on the Hill" is a song by English singer-songwriter Ed Sheeran.  It was released as a digital download on 6 January 2017 as one of the double lead singles from his third studio album "÷" (2017), along with "Shape of You".  "Castle on the Hill" was written and produced by Ed Sheeran and Benny Blanco.

How Would You Feel (Paean): "How Would You Feel (Paean)" (also known as How Would You Feel If I Told You I Loved You?)  is a song by English singer-songwriter Ed Sheeran.  It was released on the 17 February 2017 as the first promotional single from his third studio album "÷" (2017).  Upon release it charted at number 2 on the UK Singles Chart, despite not being an official single.  It has also made the top 10 in six other countries.

New Man (Ed Sheeran song): "New Man" is a song by English singer-songwriter Ed Sheeran from his third studio album "÷" (2017).  It was written and produced by Sheeran and Benny Blanco, and co-written with Ammar Malik and Jessie Ware.

÷ (album): ÷ (pronounced "divide") is the third studio album by English singer-songwriter Ed Sheeran.  It was released on 3 March 2017 through Asylum Records and Atlantic Records. " Castle on the Hill" and "Shape of You" were released as the album's lead singles on 6 January 2017.

Eraser (Ed Sheeran song): "Eraser" is a song by English singer-songwriter Ed Sheeran from his third studio album "÷" (2017).  It was written and produced by Sheeran and Johnny McDaid.  After the album's release, it charted at number 14 on the UK Singles Chart, despite not being an official single.

Supporting paragraphs: ÷ (album) Castle on the Hill (song)
Answer: Castle on the Hill