import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        long big = 0;
        long small = 0;
        for (int i = 0; i < n; i++) {
            char[] arr = sc.next().toCharArray();
            long x = 0;
            long y = 0;
            int count = 0;
            boolean isPlus = true;
            boolean hasDot = false;
            for (int j = 0; j < arr.length || (hasDot && count < 10); j++) {
                if (!hasDot && arr[j] == '-') {
                    isPlus = false;
                } else if (!hasDot && arr[j] == '.') {
                    hasDot = true;
                } else {
                    if (!hasDot) {
                        x *= 10;
                        x += arr[j] - '0';
                    } else {
                        y *= 10;
                        count++;
                        if (j < arr.length) {
                            y += arr[j] - '0';
                        }
                    }
                }
            }
            if (isPlus) {
                big += x;
                small += y;
            } else {
                big -= x;
                small -= y;
            }
        }
        if (small <= -10000000000L) {
            big += small / 10000000000L;
            small = -(-small % 10000000000L); 
        } else if (small >= 10000000000L) {
            big += small / 10000000000L;
            small %= 10000000000L;
        }
        if (big == 0 && small < 0) {
            small = -small;
            System.out.printf("-0.%010d\n", small);
            return;
        } 
        if (small < 0) {
            if (big >= 0) {
                big--;
                if (big == 0) {
                    small = -small;
                    System.out.printf("-0.%010d\n", small);
                    return;
                }
                small = 10000000000L + small;
            } else {
                small = -small;
            }
        } else {
            if (big < 0 && small != 0) {
                big++;
                small = 10000000000L - small;
                if (big == 0) {
                    System.out.printf("-0.%010d\n", small);
                    return;
                }
            }
        }
        System.out.print(big + ".");
        System.out.printf("%010d\n", small);
    }
}