He served in that position until the swearing in of Sergio Mattarella on 3 February 2015 .
On 14 January 2015 , on the resignation of Giorgio Napolitano , Grasso became the acting President of the Italian Republic .
Grasso served in that position until the swearing in of Sergio Mattarella on 3 February 2015 .
On 14 January 2015 , on the resignation of Giorgio Napolitano , Grasso became the acting President of the Italian Republic .