which city with the smallest population of all the members of the Council of Europe Chiesa di Sant'Andrea  located?
Chiesa di Sant'Andrea (Serravalle) Chiesa di Sant'Andrea (Serravalle) is a church located in Serravalle, San Marino. It was built in 1824 over the ancient walls of the former city. It belongs to the Roman Catholic Diocese of San Marino-Montefeltro. It was built in 1824. The church was dedicated to St. Andrew and the Virgin Mary.
Sant'Antioco Sant'Antioco (] ; Sardinian: "Santu Antiogu" ) is the name of both an island and a municipality ("comune") in southwestern Sardinia, in the Province of South Sardinia, in Sulcis zone. With a population of 11,730, the municipality of Sant'Antioco it is the island's largest community. It is also the site of ancient Sulci, considered the second city of Sardinia in antiquity.