#include <bits/stdc++.h>

using namespace std;

#define M 1000000007
#define pe(a,b) {a+=b;a%=M;}
#define te(a,b) {a*=b;a%=M;}

typedef int tint;
#define int unsigned long long
//memo[ind][#]. or just generate all.

int n;
int *m;
int *mem;
int *fgm;

int fg(int i,int j) {
    return fgm[i*n+j]=fgm[i*n+j-1]*(i-j+1)%M;
    /*
    int r=1;
    while(j-- && !fgm)te(r,i--);
    return r;
    */
}

int get(int i,int j) {
    if(i+j>n)return 0;
    if(mem[i*n+j])return mem[i*n+j]-1;
    int p=0;
    for(int i2=i;i2<i+j;i2++) {
        if(m[i2]<p){mem[i*n+j]=1;return 0;}
        p=m[i2];
    }
    int ret=0;
    if(i+j==n)ret++;
    else for(int j2=1;j2<=j && i+j+j2<=n;j2++) {
        pe(ret,fg(j,j2)*get(i+j,j2));
    }
    mem[i*n+j]=ret+1;
    return ret;
}

tint main(){
    cin >> n;
    int m[n]; ::m=m;
    int mem[n*n]={}; ::mem=mem;
    int fgm[(n+1)*(n+1)]={}; ::fgm=fgm;
    for(int i=0;i<=n;i++)fgm[i*n]=1;
    int pi=0;
    bool f=true;
    int prev=0;
    for(int m_i = 0; m_i < n; m_i++){
        cin >> m[m_i];
        if(m[m_i]<prev)f=false;
        if(f)pi=m_i;
        prev=m[m_i];
    }
    int res=0;
    if(f)res++;
    for(int i=0;i<=pi;i++) {
        for(int j=0;j<=i;j++) {
            pe(res,fg(i+1,j+1)*get(i+1,j+1));
        }
    }
    cout << res;
    // your code goes here
    return 0;
}