#include <iostream>
#include <math.h>
using namespace std;
int main()
{
	int n;
	cout << "n="; cin >> n;
int *a = new int[n];
	int i, s1, s2;
	s1 = s2 = 0;
	for (i = 0; i < n; i++)
	{
		cout << "a[" << i << "]="; cin >> a[i];
}
	for (i = 0; i < n / 2; i++)
if (a[i]>0)
		s1 = s1 + a[i];
	for (i = n / 2; i < n; i++)
if (a[i] < 0)
	s2 = s2 + a[i];
	cout << "s1=" << s1 << endl;
cout << "s2=" << s2<<endl;
return 0;
}