#include <bits/stdc++.h>

using namespace std;
const int N = 1220, MOD = 1000000007;
int fac[N], invfac[N], f[N][N];

void add(int &x, int y) {
    x += y;
    if (x >= MOD) {
        x -= MOD;
    }
}

int pw(int x, int y) {
    int ans = 1;
    for (; y; y >>= 1, x = 1ll * x * x % MOD) {
        if (y & 1) {
            ans = ans * 1ll * x % MOD;
        }
    }
    return ans;
}

int inv(int x) {
    return pw(x, MOD - 2);
}

int c(int x, int y) {
    if (x < y) {
        return 0;
    }
    return 1ll * fac[x] * invfac[y] % MOD * invfac[x - y] % MOD;
}

int main() {
    int n;
    cin >> n;
    vector<int> m(n);
    for (int m_i = 0; m_i < n; m_i++) {
        cin >> m[m_i];
    }
    fac[0] = 1;
    invfac[0] = inv(1);
    for (int i = 1; i < N; i++) {
        fac[i] = fac[i - 1] * 1ll * i % MOD;
        invfac[i] = inv(fac[i]);
    }
    // your code goes here
    int last = -1;
    for (int i = 0; i < n; i++) {
        if (m[i] < last) {
            break;
        }
        f[0][i] = 1;
        last = m[i];
    }
    for (int i = 0; i < n; ++i) {
        for (int j = i; j < n; ++j) {
            if (f[i][j]) {
//                cout << i << " " << j << " " << f[i][j] << endl;
                int l1 = j - i + 1;
                last = -1;
                for (int k = j + 1; k < n; ++k) {
                    int l2 = k - j;
                    if (l2 > l1 || m[k] < last) {
                        break;
                    }
                    add(f[j + 1][k], f[i][j] * 1ll * c(l1, l2) % MOD * fac[l2] % MOD);
                    last = m[k];
                }
            }
        }
    }
    int ans = 0;
    for (int i = 0; i < n; ++i) {
        add(ans, f[i][n - 1]);
    }
    cout << ans << endl;
    return 0;
}