import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;

public class A {

	static final int mod = (int)1e9 + 7;
	static int[] fac, comb[], memo[];
	static int N;
	static boolean[][] sorted;

	static int dp(int n, int k)
	{
		if(k == 0 || n == 0)
			return k + n == 0 ? 1 : 0;
		if(k > n || !sorted[N - n][N  + k - n - 1])
			return 0;
		if(memo[n][k] != -1)
			return memo[n][k];
		int ret = 0;
		for(int i = 0; i <= k; ++i)
		{
			ret += 1l * dp(n - k, k - i) * fac[k - i] % mod * comb[k][i] % mod;
			ret %= mod;
		}
		return memo[n][k] = ret;
	}

	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);

		int n = sc.nextInt(), m[] = new int[n];
		for(int i = 0; i < n; ++i)
			m[i] = sc.nextInt();
		N = n;
		sorted = new boolean[n][n];
		for(int i = 0; i < n; ++i)
		{
			int last = m[i];
			for(int j = i; j < n && m[j] >= last; ++j)
			{
				sorted[i][j] = true;
				last = m[j];
			}
		}
		fac = new int[n + 1];
		fac[0] = 1;
		for(int i = 1; i <= n; ++i)
			fac[i] = (int)(1l * i * fac[i - 1] % mod);
		comb = new int[n + 1][n + 1];
		comb[0][0] = 1;
		for(int i = 1; i <= n; ++i)
		{
			comb[i][0] = 1;
			for(int j = 1; j <= i; ++j)
				comb[i][j] = (comb[i - 1][j - 1] + comb[i - 1][j]) % mod;
		}
		memo = new int[n + 1][n + 1];
		for(int[] x: memo)
			Arrays.fill(x, -1);
		int ans = 0;
		for(int i = 1; i <= n; ++i)
			ans = (ans + dp(n, i)) % mod;
		out.println(ans);
		out.flush();
		out.close();
	}

	static class Scanner 
	{
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s){	br = new BufferedReader(new InputStreamReader(s));}

		public String next() throws IOException 
		{
			while (st == null || !st.hasMoreTokens()) 
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {return Integer.parseInt(next());}

		public long nextLong() throws IOException {return Long.parseLong(next());}

		public String nextLine() throws IOException {return br.readLine();}

		public double nextDouble() throws IOException { return Double.parseDouble(next()); }

		public boolean ready() throws IOException {return br.ready();} 
	}
}