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#include <bits/stdc++.h>
using namespace std;

const int MOD = 1e9 + 7;
const int MAX_N = 3e5 + 10;
#define AGREE 0
#define DISAGREE 1

int n; 
int a[MAX_N];

vector<int> sums;
unordered_map<int, int> order;

int possible[2][MAX_N];


inline void add_mod(int &a, int b) {
	a = (a + b) % MOD;
}

void add_result(int sum, int result) {
	int tab = sum % 2;
	int pos = order[sum];
	
	while (pos < MAX_N) {
		add_mod(possible[tab][pos], result);
		pos += (pos & (-pos));
	}
}

int get_upto(int agree, int sum) {
	int tab = (sum % 2) ^ agree;
	int pos = order[sum];
	int result = 0;
	
	while (pos > 0) {
		add_mod(result, possible[tab][pos]);
		pos -= (pos & (-pos));
	}
	
	return result;
}

int get_gthan(int agree, int sum) {
	int result = get_upto(agree, MOD + 1 - (sum % 2)) // preserve parity
				- get_upto(agree, sum);
	if (result < 0) result += MOD;
	return result;
}

void get_sums() {
	int sum = 0;
	
	sums.push_back(0);
	for (int i = n-1; i >= 0; i--) {
		add_mod(sum, a[i]);
		sums.push_back(sum);
	}
}

void get_order(vector<int> &sums) {
	sort(sums.begin(), sums.end());
	
	auto last = std::unique(sums.begin(), sums.end());
	sums.erase(last, sums.end());
	
	for (int j = 0; j < sums.size(); j++) 
		order[sums[j]] = j + 1;
		
	order[MOD] = sums.size() + 1; 		// watchman 1
	order[MOD + 1] = sums.size() + 2; 	// watchman 2
}

int get_result() {
	int sum = 0;
	int loc_result;
	
	for (int i = n-1; i >= 0; i--) {
		add_mod(sum, a[i]);
	
		loc_result = 0;
		add_mod(loc_result, get_upto(AGREE, sum));
		add_mod(loc_result, get_gthan(DISAGREE, sum));
		
		add_result(sum, loc_result);
	}
	
	return loc_result;
}

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	
	cin >> n;
	for (int i = 0; i < n; i++) cin >> a[i];
	
	get_sums();
	get_order(sums);
	
	add_result(0, 1);
	cout << get_result() << endl;
	
	return 0;
}