#include <stdio.h>
#include <math.h>
int fun(int, int) ;

int main() {
	int count = 0;
	int  a[30], i = 0;
	long long sum = 0;
	while (scanf("%d", &a[i]) != EOF) {
		count++;
		i++;
	}
	for (i = 0; i < count; i++) {
		sum = sum + fun(count, a[i]);
	}
	printf("%d", sum);
	return 0;

}

int fun(int n, int m) {
	int i;
	double k;
	int sum = 0;
	k = pow(2, n - 1);
	for (i = 0; i < k; i++)
		sum = sum + m;
	return sum;
}