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#include <cstdio>
#include <algorithm>
#define MOD 1000000007ll
#define TREE_SIZE 2147483648ll
using namespace std;
typedef long long LL;

class Node {
public:
    Node* left;
    Node* right;

    LL parSum;
    LL nParSum;

    LL leftBorder;
    LL rightBorder;

    Node(LL l, LL r) {
        this->left = NULL;
        this->right = NULL;
        this->parSum = 0;
        this->nParSum = 0;
        this->leftBorder = l;
        this->rightBorder = r;
    }
};

Node* tree = NULL;

LL sum(LL l, LL r, Node* node, bool takePar) {
    if (l > r) {
        return 0;
    }

    if (node->leftBorder == l && node->rightBorder == r) {
        return takePar ? node->parSum : node->nParSum;
    } else {
        LL ret = 0;
        if (node->left && l <= node->left->rightBorder) {
            ret += sum(l, min(node->left->rightBorder, r), node->left, takePar);
        }
        if (node->right && r >= node->right->leftBorder) {
            ret += sum(max(node->right->leftBorder, l), r, node->right, takePar);
        }
        return ret % MOD;
    }
}

void add(LL pos, Node* node, LL amount) {
    if (pos % 2 == 0) {
        node->parSum = (node->parSum + amount) % MOD;
    } else {
        node->nParSum = (node->nParSum + amount) % MOD;
    }

    LL mid = (node->leftBorder + node->rightBorder) >> 1;

    if (node->leftBorder == node->rightBorder) {
        return;
    }

    if (pos <= mid) {
        if (node->left == NULL) {
            node->left = new Node(node->leftBorder, mid);
        }
        add(pos, node->left, amount);
    } else {
        if (node->right == NULL) {
            node->right = new Node(mid + 1, node->rightBorder);
        }
        add(pos, node->right, amount);
    }
}

int main() {
    tree = new Node(0, TREE_SIZE - 1);

    LL prefSum = 0, x = 0;
    int n = 0;

    scanf("%d", &n);
    add(0, tree, 1);

    for (int i = 0; i < n; i++) {
        scanf("%lld", &x);
        prefSum = (prefSum + x) % (2 * MOD);

        LL ile = 0;

        if (prefSum < MOD) {
            ile += sum(0, prefSum, tree, prefSum % 2 == 0);
            ile += sum(prefSum + 1, prefSum + MOD, tree,prefSum % 2 == 1);
            ile += sum(prefSum + MOD + 1, 2 * MOD - 1, tree, prefSum % 2 == 0);

        } else {
            ile += sum(prefSum - MOD + 1, prefSum, tree, prefSum % 2 == 0);
            ile += sum(0, prefSum - MOD, tree, prefSum % 2 == 1);
            ile += sum(prefSum + 1, 2 * MOD - 1, tree, prefSum % 2 == 1);
        }

        ile = ile % MOD;

        add(prefSum, tree, ile);

        if (i == n - 1) {
            printf("%lld\n", ile);
        }
    }
}