#define _CRT_SECURE_NO_WARNINGS
#define TASK "insider"
#pragma comment(linker, "/STACK:671088640")
#include <stdio.h>
#include <iostream>
#include <iomanip> 
#include <math.h>
#include <time.h>
#include <stdlib.h>
#include <string.h>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <functional>
#include <assert.h>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <random>
#include <complex>
using namespace std;

const int MOD = 1000000007;
const int INF = 2000000000;
const long double EPS = 1e-6;
const int HASH_POW = 29;
const long double PI = acos(-1.0);
mt19937_64 rnd(1);

double workTime()
{
	return double(clock()) / CLOCKS_PER_SEC;
}

void my_return(int code)
{
#ifdef MYDEBUG
	cout << "\nTime = " << fixed << setprecision(3) << workTime() << endl;
#endif
	exit(code);
}

int n, p[1234], f[1234];
int c[1234][1234], dp[1234][1234];

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
#ifdef MYDEBUG
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#else
	/*freopen(TASK".in", "r", stdin);
	freopen(TASK".out", "w", stdout);*/
	/*freopen("pie_progress.txt", "r", stdin);
	freopen("pie_progress_output.txt", "w", stdout);*/
#endif

	scanf("%d", &n);
	for (int i = 1; i <= n; ++i)
		scanf("%d", &p[i]);

	f[0] = 1;
	for (int i = 1; i < 1234; ++i)
		f[i] = f[i - 1] * 1ll * i % MOD;
	c[0][0] = 1;
	for (int i = 1; i < 1234; ++i)
	{
		c[i][0] = 1;
		for (int j = 1; j <= i; ++j)
			c[i][j] = (c[i - 1][j - 1] + c[i - 1][j]) % MOD;
	}

	for (int r = 1; r <= n; ++r)
	{
		bool good = true;
		for (int j = 1; j < r; ++j)
		{
			if (j > 1 && p[r - j + 1] > p[r - j + 2])
			{
				good = false;
				break;
			}
			dp[r][j] = 0;
			for (int len = j; len <= r; ++len)
			{
				int delta = dp[r - j][len] * 1ll * c[len][j] % MOD;
				delta = delta * 1ll * f[j] % MOD;
				dp[r][j] = (dp[r][j] + delta) % MOD;
			}
		}
		if (r > 1 && p[1] > p[2])
			good = false;
		if (good)
			dp[r][r] = 1;
		else
			dp[r][r] = 0;
	}
	int ans = 0;
	for (int j = 1; j <= n; ++j)
		ans = (ans + dp[n][j]) % MOD;
	printf("%d\n", ans);

	my_return(0);
}