#include <bits/stdc++.h>

#define M 1000000007ll
#define ll long long
#define MIN(x, y) ((x) < (y) ? (x) : (y))
#define MAX(x, y) ((x) < (y) ? (y) : (x))

using namespace std;
const int N = 200020;

ll C[2020][2020], S[2020][2020];
int n;
int a[2020];
ll answer;

int main()
{
  scanf("%d", &n);

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

  C[0][0] = 1;
  for(int i = 0; i <= n; ++ i)
  {
    ll now = 1;
    C[i][0] = 1;
    for(int j = i + 1; j <= n; ++ j)
    {
      now = (now * j) % M;
      C[j][j - i] = now;
    }
  }

  S[n + 1][0] = 1;
  for(int i = n + 1; i > 0; -- i)
  {
    for(int j = i - 1; j > 0; -- j)
    {
      if((i - 1 - j) && a[j] > a[j + 1])
        break;
      for(int p = 0; p <= i - j; ++ p)
      {
        ll x = (S[i][p] * C[i - j][p]) % M;
        S[j][i - j] = (S[j][i - j] + x) % M;
      }
    }
  }
  for(int p = 0; p <= n; ++ p)
    answer = (answer + S[1][p]) % M;
  printf("%lld", answer);
}