#include <stdio.h>
#include <stdlib.h>



int main()
{
	int i, j, k, n;
	long long d, s = 0;
	char a[22];

	scanf("%d", &n);

	for (i = 0; i < n; i++) {
		scanf("%s", a);
		d = 0;
		for (j = 0; a[j] != '.' && a[j] != '\0'; j++)
			d = d * 10 + (long long)(a[j] - '0');
		k = 10;
		if (a[j] == '.') {
			j++;
			for (; a[j] != '\0'; j++) {
				d = d * 10 + (long long)(a[j] - '0');
				k--;
			}
			j--;
		}
		for (; k > 0; k--)
			d *= 10;
		s += d;
	}

	printf("%lld.", s / 10000000000);
	printf("%lld\n", s % 10000000000);

	return EXIT_SUCCESS;
}