#include<iostream>
using namespace std;
 
int bellNumber(int n)
{
   int bell[n+1][n+1];
   bell[0][0] = 1;
   for (int i=1; i<=n; i++)
   {
      // Explicitly fill for j = 0
      bell[i][0] = bell[i-1][i-1];
 
      // Fill for remaining values of j
      for (int j=1; j<=i; j++)
         bell[i][j] = bell[i-1][j-1] + bell[i][j-1];
   }
   return bell[n][0];
}
 
// Driver program
int main()
{
   int n;
   cin>>n;
   int a[n];
   for(int i=0;i<n;i++)
   cin>>a[n];
      cout <<  (bellNumber(n)-1) % (10^9 + 7) << endl;
   return 0;
}