#include <iostream>
#include <vector>

using namespace std;

const long long base = 1e9 + 7;

long long mul(long long a, long long b) {
	return a * b % base;
}

void add(long long &a, long long diff) {
	a += diff;
	if (a >= base)
		a -= base;
	if (a < 0)
		a += base;
}

const int maxn = 1202;

long long f[maxn][maxn];
long long sum[maxn][maxn];
long long prod[maxn][maxn];


int main() {
	int n = 0;
	cin >> n;
	vector < int > v(n + 1, 0);
	for (int i = 0; i < n; i++)
		cin >> v[i];
	v[n] = n + 1;
	f[n][0] = 1;
	for (int i = 0; i <= n; i++)
		sum[n][i] = 1;
	vector < int > a(n + 1, 0);
	for (int i = n - 1; i >= 0; i--) {
		a[i] = a[i + 1] + 1;
		if (v[i] > v[i + 1])
			a[i] = 1;
	}

	for (int i = 0; i <= n; i++) {
		prod[i][i] = max(i, 1);
		for (int j = i + 1; j <= n; j++)
			prod[i][j] = mul(prod[i][j - 1], j);
	}
	for (int i = n - 1; i >= 0; i--) {
		for (int k = 1; k <= a[i]; k++) {
			if (i + k == n)
				add(f[i][k], 1);
			for (int j = 1; j <= k; j++) {
				if (i + k < n)
					add(f[i][k], mul(prod[k - j + 1][k], f[i + k][j]));
			}

		}
	}
	long long sum = 0;
	for (int i = 0; i <= n; i++)
		add(sum, f[0][i]);
	cout << sum << endl;
	return 0;
}