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

typedef long long ll;
typedef pair<int, int> pii;
typedef tuple<int, int, int> tii;
typedef vector<int> vi;

#define pb push_back
#define eb emplace_back
#define all(s) (s).begin(), (s).end()
#define rep(i, a, b) for (int i = (a); i <= (b); ++i)
#define per(i, a, b) for (int i = (a); i >= (b); --i)

int n, m, L, l[10];

vector<vi> S[8];

void dfs(int l, int mn, vi s) {
    if (l == 0) {S[L].eb(s); return;}
    rep(i, mn, m) {
        s.eb(i);
        dfs(l - 1, i + 1, s);
        s.pop_back();
    }
}

inline void work() {
    rep(i, 1, 7) l[i] = 0;
    rep(i, 1, n) {
        S[i].clear();
        int w; cin >> w;
        rep(j, 1, w) l[j] = i;
    }
    cin >> m;
    rep(i, 1, n) {L = i; dfs(i, 1, vector<int>{});}
    vector<ll> dp[8];
    for (n = 7; l[n] == 0; --n);
    auto check = [&](vi nw, vi pre) {
        rep(i, 0, (int)nw.size() - 1) if (nw[i] < pre[i]) return false;
        return true;
    };
    rep(i, 0, (int)S[l[1]].size() - 1) dp[1].eb(1);
    rep(i, 2, n) {
        rep(j, 0, (int)S[l[i]].size() - 1) {
            ll ans = 0;
            rep(k, 0, (int)S[l[i - 1]].size() - 1)
                if (check(S[l[i]][j], S[l[i - 1]][k])) ans += dp[i - 1][k];
            dp[i].eb(ans);
        }
    }
    ll ANS = 0;
    for (auto x : dp[n]) ANS += x;
    printf("%lld\n", ANS);
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    while (cin >> n) work();
    return 0;
}