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#include <stdio.h>
#include <vector>

constexpr auto MOD = 1000000007;

//open source implementation of RedBlackTree taken from:
//https://github.com/jakobkogler/Algorithm-DataStructures/blob/master/BST/RedBlackTree.h
template <typename Key, typename Value>
class RedBlackTreeNode
{
public:
	RedBlackTreeNode(Key key, Value value) : key(key), value(value), left(nullptr), right(nullptr), color(Color::red)
	{
	}

	static RedBlackTreeNode<Key, Value> *rotateLeft(RedBlackTreeNode<Key, Value> *h)
	{
		RedBlackTreeNode<Key, Value> *x = h->right;
		h->right = x->left;
		h->rightSum = x->leftSum;

		x->left = h;
		x->leftSum = ((x->leftSum + h->value) % MOD + h->leftSum) % MOD;

		x->color = h->color;
		h->color = Color::red;
		return x;
	}

	static RedBlackTreeNode<Key, Value> *rotateRight(RedBlackTreeNode<Key, Value> *h)
	{
		RedBlackTreeNode<Key, Value> *x = h->left;
		h->left = x->right;
		h->leftSum = x->rightSum;

		x->right = h;
		x->rightSum = ((x->rightSum + h->value) % MOD + h->rightSum) % MOD;

		x->color = h->color;
		h->color = Color::red;
		return x;
	}

	static void flipColors(RedBlackTreeNode<Key, Value> *h)
	{
		h->color = Color::red;
		h->left->color = Color::black;
		h->right->color = Color::black;
	}

	static bool isRed(RedBlackTreeNode<Key, Value> *node)
	{
		if (node == nullptr)
			return false;
		return node->color == Color::red;
	}

	static RedBlackTreeNode<Key, Value> *add(RedBlackTreeNode<Key, Value> *node, Key key, Value value)
	{
		if (node == nullptr)
		{
			return new RedBlackTreeNode<Key, Value>(key, value);
		}
		if (key == node->key)
		{
			node->value = (node->value + value) % MOD;
		}
		else if (key < node->key)
		{
			node->left = add(node->left, key, value);
			node->leftSum = (node->leftSum + value) % MOD;
		}
		else
		{
			node->right = add(node->right, key, value);
			node->rightSum = (node->rightSum + value) % MOD;
		}

		if (!isRed(node->left) && isRed(node->right))
			node = rotateLeft(node);

		if (isRed(node->left) && isRed(node->right))
			flipColors(node);

		return node;
	}

	static bool contains(RedBlackTreeNode *node, Value elem)
	{
		if (node == nullptr)
			return false;

		if (elem < node->key)
			return contains(node->left, elem);
		else if (elem == node->key)
			return true;
		else
			return contains(node->right, elem);
	}

	static Value sum(RedBlackTreeNode *node, const Key &left, const Key &right, const bool useLeftSum, const bool useRightSum)
	{
		Value buffer{0};
		if (left <= node->key && node->key <= right)
		{
			buffer = (buffer + node->value) % MOD;

			if (useLeftSum)
				buffer = (buffer + node->leftSum) % MOD;
			else if (node->left)
				buffer = (buffer + sum(node->left, left, node->key - 1, false, true)) % MOD;

			if (useRightSum)
				buffer = (buffer + node->rightSum) % MOD;
			else if (node->right)
				buffer = (buffer + sum(node->right, node->key + 1, right, true, false)) % MOD;
		}
		else
		{
			if (right < node->key)
			{
				if (node->left)
				{
					buffer = (buffer + sum(node->left, left, right, false, false)) % MOD;
				}
			}
			else
			{
				if (node->right)
				{
					buffer = (buffer + sum(node->right, left, right, false, false)) % MOD;
				}
			}
		}
		return buffer;
	}

private:
	enum Color
	{
		black,
		red
	};

	Key key;
	Value value;
	Value leftSum{0};
	Value rightSum{0};
	RedBlackTreeNode *left, *right;
	Color color;
};

template <typename Key, typename Value>
class RedBlackTree
{
public:
	RedBlackTree() : root(nullptr)
	{
	}

	void add(Key key, Value value)
	{
		if (root == nullptr)
		{
			root = new RedBlackTreeNode<Key, Value>(key, value);
		}
		else
		{
			root = RedBlackTreeNode<Key, Value>::add(root, key, value);
		}
	}

	bool contains(Key elem)
	{
		if (root == nullptr)
		{
			return false;
		}
		else
		{
			return RedBlackTreeNode<Key, Value>::contains(root, elem);
		}
	}

	Value sum(Key left, Key right)
	{
		if (root == nullptr)
		{
			return 0;
		}
		else
		{
			return RedBlackTreeNode<Key, Value>::sum(root, left, right, false, false);
		}
	}

private:
	RedBlackTreeNode<Key, Value> *root;
};

int solution(const std::vector<int> &numbers)
{
	int closeSectionPermutation{1};
	RedBlackTree<int, int> even;
	RedBlackTree<int, int> odd;

	int factor{0};
	for (const auto number : numbers)
	{
		int newCloseSectionPermutation{0};

		factor = (factor + number) % MOD;
		const auto inverseFactor = (MOD - factor);
		if (factor % 2 == 0)
		{
			newCloseSectionPermutation = (newCloseSectionPermutation + even.sum(0, inverseFactor)) % MOD;
			newCloseSectionPermutation = (newCloseSectionPermutation + odd.sum(inverseFactor, MOD)) % MOD;
		}
		else
		{
			newCloseSectionPermutation = (newCloseSectionPermutation + odd.sum(0, inverseFactor)) % MOD;
			newCloseSectionPermutation = (newCloseSectionPermutation + even.sum(inverseFactor, MOD)) % MOD;
		}

		if (0 < closeSectionPermutation)
		{
			if (number % 2 == 0)
			{
				newCloseSectionPermutation = (newCloseSectionPermutation + closeSectionPermutation) % MOD;
			}
			const auto index = (number + MOD - factor) % MOD;
			if (index % 2 == 0)
				even.add(index, closeSectionPermutation);
			else
				odd.add(index, closeSectionPermutation);
		}

		closeSectionPermutation = newCloseSectionPermutation;
	}

	return closeSectionPermutation;
}

int main()
{
	int n, number;
	scanf("%d\n", &n);
	std::vector<int> numbers;
	for (int i = 0; i < n; ++i)
	{
		scanf("%d", &number);
		numbers.push_back(number);
	}
	printf("%d\n", solution(numbers));
	return 0;
}