import java.util.Scanner; public class Main_yukicoder81 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); long decimal = 0; long intp = 0; for (int i = 0; i < n; i++) { String a = sc.next(); int index = a.indexOf('.'); if (index == -1) { intp += Long.parseLong(a); } else { long sign = 1; if (a.charAt(0) == '-') { sign = -1; } intp += Long.parseLong(a.substring(0, index)); String tmp = a.substring(index + 1); while (tmp.length() < 10) { tmp += "0"; } decimal += sign * Long.parseLong(tmp); } } intp += decimal / 10000000000L; decimal %= 10000000000L; if (decimal < 0) { intp--; decimal += 10000000000L; } decimal %= 10000000000L; System.out.printf("%d.%010d\n", intp, decimal); sc.close(); } }