#include <stdio.h>

int max(int a, int b)
{
	if (a > b)
		return a;
	else
		return b;
}

int main()
{
	int triangle[100][100];
	int sol[100][100];
	int i, j, n, a;

	n = 0;
	while (scanf("%d", &a)!=EOF) {
		triangle[n][0] = a;
		for (i = 1; i <= n; i++)
			scanf("%d", &triangle[n][i]);
		n++;
	}

	for (i = 0; i < n; i++)
		sol[n-1][i] = triangle[n-1][i];

	for (i = n-2; i >= 0; i--) {
		for (j = 0; j <= i; j++) {
			sol[i][j] = triangle[i][j] + max(sol[i+1][j], sol[i+1][j+1]);
		}
	}

	printf("%d\n", sol[0][0]);
}