#include<bits/stdc++.h>
#define mod 1000000007
#define C(n,k) ( ( (fact[n]*factin[n-k])%mod) * factin[k])%mod
#define P(n,k) ( (fact[n]*factin[n-k])%mod)%mod
using namespace std;
long long D [ 1201 ] [ 1201 ]  , fact [ 1250 ] , factin [ 1250 ] ;
int crec [ 1201 ] , n ;
long long expo ( long long b , int ex ) {
	if ( ex == 0 ) return 1 ;
	if ( ex == 1 ) return b ;
	long long r = expo ( b , ex >> 1 ) ;
	if ( ex & 1 ) return  ( ( ( r * r ) % mod ) * b ) % mod ;
	return ( r * r ) % mod ;
}
long long dp (int p , int x ){

	if ( p + x > crec [ p ] || p + x > n) return 0 ;
	if ( p + x == n ) return 1 ;
	if ( D [ p ] [ x ] != -1 ) return D [ p ] [ x ] ;
	long long ans = 0 ;
	for ( int i = 1 ; i <= x ; i ++ ) ans = ( ans +  dp ( p + x , i ) * P ( x , i ) ) % mod  ;
	return D [ p ] [ x ] = ans;
}
int main(){
	ios::sync_with_stdio ( 0 ) ;
	cin.tie ( NULL ) ;
	memset ( D , -1 , sizeof D ) ;
	fact [ 0 ] = factin [ 0 ] = 1 ;
	for( long long i = 1 ; i < 1250 ; i++ ) fact [ i ] = ( fact [ i - 1 ] * i ) % mod ;
	for ( int i = 1 ; i < 1250 ; i ++ ) factin [ i ] = expo ( fact[i] , 1000000005 ) ;
	cin >> n ;
	int x = 0 ;
	vector<int> v ( n ) ;
	int b = 0 ;
	for ( int i = 0 ; i < n ; i ++ ) {
		cin >> v [ i ] ;
		if ( i > 0 ) if ( v [ i ] < v [ i - 1 ] ) while ( b < i ) crec [ b ++ ] = i ;
	}
	while ( b < n ) crec [ b ++ ] = n ;
	long long re = 0 ;
	for(int i = 1 ; i <= crec[0] ; i ++ ) re = ( re + dp ( 0 , i ) ) % mod ;
	cout << re % mod << endl ;
	return 0;
}