//#pragma GCC optimize("Ofast", "unroll-loops")
//#pragma GCC target("sse", "sse2", "sse3", "ssse3", "sse4")

#include <bits/stdc++.h>

#define all(a) a.begin(),a.end()
#define len(a) (int)(a.size())
#define mp make_pair
#define pb push_back
#define fir first
#define sec second
#define fi first
#define se second

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;

template<typename T>
bool umin(T &a, T b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}
template<typename T>
bool umax(T &a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

#ifdef KIVI
#define DEBUG for (bool _FLAG = true; _FLAG; _FLAG = false)
#define LOG(...) print(#__VA_ARGS__" ::", __VA_ARGS__) << endl
template <class ...Ts> auto &print(Ts ...ts) { return ((cerr << ts << " "), ...); }
#else
#define DEBUG while (false)
#define LOG(...)
#endif

const int max_n = 2000+10, inf = 1000111222;

const ll mod = 2147483647;

ll dp[max_n][max_n];

void inc(ll& a,ll b)
{
    a+=b;
    if (a>=mod){
        a-=mod;
    }
}

int a[max_n];

int main() {
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);

    ios_base::sync_with_stdio(0);
    cin.tie(0);


    int n;
    cin>>n;
    for (int i=0;i<=n;i++){
        cin>>a[i];
    }
    dp[1][a[0]]=1;
    for (int i=1;i<n;i++){
        for (int j=1;j<=n+1;j++){
            int L=j;
            int R=a[i];
            if (L>R){
                swap(L,R);
            }

            if (L<=a[i+1] && a[i+1]<=R){
                inc(dp[i+1][j],dp[i][j]);
                inc(dp[i+1][a[i]],dp[i][j]);
            }
            else if (a[i+1]<L){
                inc(dp[i+1][R],dp[i][j]);
            }
            else if (a[i+1]>R){
                inc(dp[i+1][L],dp[i][j]);
            }
            else{
                assert(0);
            }
        }
    }
    ll ans=0;
    for (int i=1;i<=n+1;i++){
        inc(ans,dp[n][i]);
    }
    cout<<ans<<"\n";
}