#include <bits/stdc++.h>
#define FAST ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);cerr.tie(0)
#define mp make_pair
#define xx first
#define yy second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define all(x) x.begin(),x.end()
#define ff(i,a,b) for (int i = a; i < b; i++)
#define fff(i,a,b) for (int i = a; i <= b; i++)
#define bff(i,a,b) for (int i = b-1; i >= a; i--)
#define bfff(i,a,b) for (int i = b; i >= a; i--)
using namespace std;
long double typedef ld;
unsigned int typedef ui;
long long int typedef li;
pair<int,int> typedef pii;
pair<li,li> typedef pli;
pair<ld,ld> typedef pld;
vector<vector<int>> typedef graph;
unsigned long long int typedef ull;
//const int mod = 998244353;
//const int mod = 1000000007;
//Note to self: Check for overflow
const int mod=1000007;
int niz[10004];
int dp[10004];
int main()
{
FAST;
int n; cin>>n;
fff(i,1,n) cin>>niz[i];
int dosad=1;
fff(i,2,n)
{
bfff(j,1,n) dp[j]=((li)dp[j]*j%mod+dp[j-1])%mod;
(dp[dosad]+=niz[i]-1)%=mod; dosad=max(dosad,niz[i]);
}
int ans=1;
fff(i,1,n) (ans+=dp[i])%=mod;
cout<<ans<<"\n";
}
//Note to self: Check for overflow
