#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define foru(a,b,c) for(ll a=b;a<=c;a++)

ll n,a[25],cnt;

int main(){
    freopen("changgao_perm.in" ,"r",stdin );
    freopen("changgao_perm.out","w",stdout);
    cin>>n;
    foru(i,1,n){
        cin>>a[i];
    }
    foru(i,1,n-1){
        foru(j,i+1,n){
            if(i<j&&a[i]>a[j]){
                cnt++;
            }
        }
    }
    cout<<(1<<cnt)%1000000007;
    return 0;
}