#include <bits/stdc++.h>

using namespace std;

#define _ ios_base::sync_with_stdio(0);cin.tie(0);
#define endl '\n'
#define pb push_back
#define f first
#define s second

typedef long long ll;

const int MAX = 1e6+10;
const int MOD = 1e9+7;
const int inf = 0x3f3f3f3f;

int seg[2*MAX];
int fat[2*MAX];
int n;
int maxi = 0;
vector<vector<int>> w(MAX);

ll fexp(ll x, ll y){
    ll ret = 1;
    while(y){
        if(y&1) ret = (ret*x) %MOD;
        y >>=1;
        x = (x*x)%MOD;
    }
    return ret;
}

ll inv(ll x){
    return fexp(x, MOD-2);
}

void fat_build(){
    for(ll i=2; i<2*MAX; i++)
        fat[i] = ((ll)fat[i-1]*i)%MOD;
}

// cat(n) = (2*n)!/ ((n+1)! * n!)
ll cat(ll x){
    if(x==1) return 1;
    return fat[2*x]%MOD * inv(fat[x+1])%MOD * inv(fat[x])%MOD;
}

int build(){
    for(int i=n-1; i; i--) seg[i] = min(seg[2*i], seg[2*i+1]);
}

int query(int a, int b){
    int ret = inf;
    for(a +=n, b+=n; a<=b; ++a /= 2, --b/=2){
        ret = min(ret, seg[a]);
        ret = min(ret, seg[b]);
    }
    return ret;
}

int main(){ _
    fat[0] = fat[1] = 1;
    fat_build();

    cin >> n;
    if(n==0){
        cout << 1 << endl;
        exit(0);
    }
    for(int i=0; i<n; i++){
        cin >> seg[n+i];
        w[seg[n+i]].pb(i);
    }

    build();

    ll ret = 1, at = 1;
    for(int i=0; i<MAX; i++){
        if(w[i].size()<2) continue;
        for(int j=0; j<w[i].size()-1; j++){
        //  cout << "num " << i << " " << j << endl;
        //  cout << "inter " << w[i][j] << " " << w[i][j+1] << endl;

            int q = query(w[i][j], w[i][j+1]);
    //      cout << i << " " << w[i][j] << " " << q << endl;
            if(q<i){
                ret = (ret*cat(at))%MOD;
                at = 1;
            }
            else{
                at++;
            }
        }
        ret = (ret*cat(at))%MOD;
        at = 1;
    }

    cout << ret << endl;

    exit(0);
}