//package Awesome;



import java.awt.Point;
import java.io.*;
 
import java.util.*;
 
 
 
 
 
 
 
 
 
 class TestClass {
 
static long mod ;
static boolean F;
static String A;


public static boolean check(int i , String C, int co){
	
      if(A.length()==i && co==1) return true;
      
      long x = Long.parseLong(C)+1;
      String B = Long.toString(x);
      
      if(i+B.length()>A.length()) return false;
      
      String D = A.substring(i,i+B.length());
      
      if(D.equals(B))
    	  return check(i+B.length(),B,1);
      
      
      
      return false;
}


public static void main(String args[] ) throws java.lang.Exception {
 
 
 
InputStream inputStream = System.in;
InputReader in = new InputReader(inputStream);
 
//BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
//BufferedReader in = new BufferedReader(new FileReader("C:\\Users\\sompatha\\Desktop\\yes.txt"));
//Scanner in = new Scanner(new FileReader("C:\\Users\\Sompathak\\Desktop\\yes.txt"));
 //PrintWriter pw = new PrintWriter(new FileWriter("C:\\Users\\sompatha\\Desktop\\output.txt"));
//InputStream inputStream = System.in;
//InputReader in = new InputReader(inputStream);
//Scanner in = new Scanner(new InputStreamReader(System.in));
//Scanner in = new Scanner(new FileReader("C:\\Users\\sompatha\\Desktop\\yes.txt"));
//we can we will ??? !!!!!! SOM RISES
//long startTime = System.currentTimeMillis();
//long startTime = System.currentTimeMillis();
 
//float endTime   = System.currentTimeMillis();
//float totalTime = (endTime - startTime)/(float)1000;
//System.out.println(totalTime+" sec....."); 
//System.out.println(check(2,2)+" "+check_2(2,2));
int n = in.nextInt();
int[] A = new int[n+1];
for(int i=1;i<=n;i++) A[i]= in.nextInt();
boolean[][] V = new boolean[n+1][n+1];
for(int i=1;i<=n;i++){
	
	int prev=-1;
	for(int j=i;j<=n;j++){
		
		if(prev>A[j]) break;
		prev=A[j];
		V[i][j]=true;
		  
	}
		
}

mod = (long) (1e9+7);
long ans =0;
long[][] dp = new long[n+1][n+1];


long[][] C = new long[1201][1201];

for(int i=1;i<=1200;i++)
	for(int j=0;j<=i;j++){
		
		  if(i==j || j==0) C[i][j]=1;
		  else C[i][j] = C[i-1][j-1] + C[i-1][j];
		  C[i][j]%=mod;
	}

for(int i=1;i<=n;i++)
	if(V[1][i]) dp[i][i]=1;

long[] Fact = new long[1201];
Fact[0]=1;
for(int i=1;i<=1200;i++) Fact[i] = (Fact[i-1]*i)%mod;

for(int i=2;i<=n;i++){
	
	  for(int j=1;j<=n;j++){
		  
		    if(i+j-1>n || !V[i][i+j-1]) break;
		    
		 for(int k=j;k<=i;k++){
			 
			 
			 
			 dp[j][i+j-1]+= dp[k][i-1]*(  (C[k][j]*Fact[j])%mod  );
			 dp[j][i+j-1]%=mod;
			 
		 }
		    
	  }
}
ans=0;
for(int i=1;i<=n;i++){
	ans+=dp[i][n];
	ans%=mod;
}
System.out.println(ans);

}public static class InputReader
{
private InputStream stream;
private byte[] buf = new byte[1024];
private int curChar;
private int numChars;
private SpaceCharFilter filter;
 
public InputReader(InputStream stream)
{
this.stream = stream;
}
 
public int read()
{
if (numChars == -1)
throw new InputMismatchException();
if (curChar >= numChars)
{
curChar = 0;
try
{
numChars = stream.read(buf);
} catch (IOException e)
{
throw new InputMismatchException();
}
if (numChars <= 0)
return -1;
}
return buf[curChar++];
}
 
public int nextInt()
{
int c = read();
while (isSpaceChar(c))
c = read();
int sgn = 1;
if (c == '-')
{
sgn = -1;
c = read();
}
int res = 0;
do
{
if (c < '0' || c > '9')
throw new InputMismatchException();
res *= 10;
res += c - '0';
c = read();
} while (!isSpaceChar(c));
return res * sgn;
}
 
public String readString()
{
int c = read();
while (isSpaceChar(c))
c = read();
StringBuilder res = new StringBuilder();
do
{
res.appendCodePoint(c);
c = read();
} while (!isSpaceChar(c));
return res.toString();
}
public double readDouble() {
int c = read();
while (isSpaceChar(c))
c = read();
int sgn = 1;
if (c == '-') {
sgn = -1;
c = read();
}
double res = 0;
while (!isSpaceChar(c) && c != '.') {
if (c == 'e' || c == 'E')
return res * Math.pow(10, nextInt());
if (c < '0' || c > '9')
throw new InputMismatchException();
res *= 10;
res += c - '0';
c = read();
}
if (c == '.') {
c = read();
double m = 1;
while (!isSpaceChar(c)) {
if (c == 'e' || c == 'E')
return res * Math.pow(10, nextInt());
if (c < '0' || c > '9')
throw new InputMismatchException();
m /= 10;
res += (c - '0') * m;
c = read();
}
}
return res * sgn;
}
public long readLong() {
int c = read();
while (isSpaceChar(c))
c = read();
int sgn = 1;
if (c == '-') {
sgn = -1;
c = read();
}
long res = 0;
do {
if (c < '0' || c > '9')
throw new InputMismatchException();
res *= 10;
res += c - '0';
c = read();
} while (!isSpaceChar(c));
return res * sgn;
}
public boolean isSpaceChar(int c)
{
if (filter != null)
return filter.isSpaceChar(c);
return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
}
 
public String next()
{
return readString();
}
 
public interface SpaceCharFilter
{
public boolean isSpaceChar(int ch);
}
}
}