#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
const long long modul = 1000000007;

long long fakt[1300],bin[1500][1500],dp[1500][1500];
long long a[2000],n;

int main() {
    scanf("%lld",&n);
    for (long long i=n;i>=1;i--)scanf("%lld",&a[i]);
    fakt[0]=1;
    for (long long i=1;i<=1200;i++){fakt[i]=fakt[i-1]*1LL*i;fakt[i]%=modul;}
    bin[0][0]=1;
    for (long long i=1;i<=n;i++)
        for (long long j=0;j<=n;j++)
    {
        if (j==0){bin[i][j]=1;continue;}
        bin[i][j]=bin[i-1][j]+bin[i-1][j-1];
        bin[i][j]%=modul;
    }

    dp[1][1]=1;
    //for (int i=0;i<=1200;i++)dp[0][i]=1;
    for (long long i=2;i<=n;i++)
    {
        long long pok = i;
        for (long long j=i-1;j>=1;j--)if (a[j]<a[j+1]){pok = i-j;break;}

        //cout<<i<<" "<<pok<<endl;
        for (long long j=1;j<=pok;j++)
        {
            for (long long z = 1;z<=i-j;z++)
            {
                long long temp = bin[j][z]*fakt[z];
                temp%=modul;
                temp*=dp[i-j][z];temp%=modul;
                dp[i][j]+=temp;dp[i][j]%=modul;
            }
            if (i==j)dp[i][j]++,dp[i][j]%=modul;
        }
    }
    long long sol=0;
  /* for (int i=1;i<=n;i++)
   {
       cout<<endl;
       for (int j=1;j<=n;j++)cout<<dp[i][j]<<" ";
   }*/
    for (long long i=1;i<=n;i++)sol+=dp[n][i],sol%=modul;
    cout<<sol<<endl;

    return 0;
}