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

int main () {
	char cur[20];
	int cur_sum = 0;
	int max = 0;
	int second = 0;
	int third = 0;

	while (fgets(cur,20,stdin) != NULL) {
		if (strlen(cur) > 1) {
			cur_sum += atoi(cur);
			if (cur_sum > max) {
				max = cur_sum;
			} else if (cur_sum > second) {
				second = cur_sum;
			} else if (cur_sum > third) {
				third = cur_sum;
			}
		} else {
			cur_sum = 0;
		}
		
	}
	printf("%d\n", max+second+third);

}