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

int main()
{
	int64_t n;
	cin >> n;
	vector<int64_t> as(n + 1, 0);
	for (int64_t i = 1; i <= n; i++)
	{
		cin >> as[i];
	}

	int64_t sum = accumulate(as.begin(), as.end(), int64_t(0));

	while (as[0] != sum)
	{
		bool f = true;
		for (int64_t i = 1; i <= n; i++)
		{
			if (as[i] == i)
			{
				f = false;
				as[i] = 0;
				for (int64_t j = i - 1; 0 <= j; j--)
				{
					as[j]++;
				}
				break;
			}
		}

		if (f)
		{
			cout << "No" << endl;
			return 0;
		}
	}

	cout << "Yes" << endl;

	return 0;
}