import java.io.*; import java.util.*; import java.util.stream.*; public class Main { public static void main(String[] args) throws Exception { Scanner sc = new Scanner(); int n = sc.nextInt(); long big = 0; long small = 0; for (int i = 0; i < n; i++) { String s = sc.next(); int idx = s.indexOf("."); if (idx < 0) { big += Long.parseLong(s); } else { if (s.charAt(0) == '-') { big -= Long.parseLong(s.substring(1, idx)); int length = s.length() - idx; small -= Long.parseLong(s.substring(idx + 1, s.length())) * pow(10, 10 - length + 1); } else { big += Long.parseLong(s.substring(0, idx)); int length = s.length() - idx; small += Long.parseLong(s.substring(idx + 1, s.length())) * pow(10, 10 - length + 1); } } } while (small < 0) { big--; small += 10000000000L; } big += small / 10000000000L; small %= 10000000000L; System.out.println(big + "." + small); } static long pow(long x, int p) { if (p == 0) { return 1; } else { return pow(x, p - 1) * x; } } } class Utilities { static String arrayToLineString(Object[] arr) { return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n")); } static String arrayToLineString(int[] arr) { return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new)); } } class Scanner { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); StringTokenizer st = new StringTokenizer(""); StringBuilder sb = new StringBuilder(); public Scanner() throws Exception { } public int nextInt() throws Exception { return Integer.parseInt(next()); } public long nextLong() throws Exception { return Long.parseLong(next()); } public double nextDouble() throws Exception { return Double.parseDouble(next()); } public int[] nextIntArray() throws Exception { return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray(); } public String next() throws Exception { while (!st.hasMoreTokens()) { st = new StringTokenizer(br.readLine()); } return st.nextToken(); } }