#include<stdio.h>
int main()
{
	int n;
	scanf("%d", &n);
	int a[1003];
	char c[102];
	int i, j;
	for (i = 0; i < n; i++)
	{
		scanf("%*c");
		scanf("%[^\n ]", &c);
		if (c[0] == '+')
			a[i] = -1;
		else if (c[0] == '-')
			a[i] = -2;
		else
		{
			a[i] = 0;
			for (j = 0; c[j] != '\0'; j++)
				a[i] = 10 * a[i] + c[j] - '0';
		}
	}
	int b[100005], bb = 0;
	for (i = 0; i < n; i++)
	{
		if (a[i] >= 0)
		{
			b[bb] = a[i];
			bb++;
		}
		else if (a[i] == -1)
		{
			b[bb - 2] += b[bb - 1];
			bb--;
		}
		else
		{
			b[bb - 2] -= b[bb - 1];
			bb--;
		}
	}
	printf("%d\n", b[0]);
	return 0;
}