#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

const long long INF = 1e18;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int r_max;
    cin >> r_max;
    vector<int> t(r_max);
    for (int i = 0; i < r_max; ++i) {
        cin >> t[i];
    }

    int k;
    cin >> k;
    vector<int> c(k);
    for (int i = 0; i < k; ++i) {
        cin >> c[i];
    }

    int m;
    cin >> m;
    int max_loc = k;
    vector<tuple<int, int, int>> edges;
    for (int i = 0; i < m; ++i) {
        int u, v, d;
        cin >> u >> v >> d;
        edges.emplace_back(u, v, d);
        max_loc = max({max_loc, u, v});
    }

    int n = max_loc;

    // --- Floyd-Warshall for All-Pairs Shortest Paths ---
    vector<vector<long long>> dist(n + 1, vector<long long>(n + 1, INF));
    for (int i = 1; i <= n; ++i) {
        dist[i][i] = 0;
    }
    for (const auto& edge : edges) {
        int u, v, d;
        tie(u, v, d) = edge;
        dist[u][v] = min(dist[u][v], (long long)d);
        dist[v][u] = min(dist[v][u], (long long)d);
    }

    for (int p = 1; p <= n; ++p) {
        for (int i = 1; i <= n; ++i) {
            for (int j = 1; j <= n; ++j) {
                if (dist[i][p] != INF && dist[p][j] != INF) {
                    dist[i][j] = min(dist[i][j], dist[i][p] + dist[p][j]);
                }
            }
        }
    }

    // --- Dynamic Programming ---
    // dp[i][j]: min time to drink i pints, ending at pub j
    vector<vector<long long>> dp(r_max + 1, vector<long long>(k + 1, INF));

    // Base Case: 1st pint
    for (int j = 1; j <= k; ++j) {
        if (dist[1][j] != INF) {
            long long finish_time = dist[1][j] + t[0];
            if (finish_time <= c[j - 1]) {
                dp[1][j] = finish_time;
            }
        }
    }

    // DP transitions
    for (int i = 2; i <= r_max; ++i) {
        for (int j = 1; j <= k; ++j) {
            long long min_arrival_time = INF;
            for (int p = 1; p <= k; ++p) {
                if (p == j) continue;
                if (dp[i - 1][p] != INF && dist[p][j] != INF) {
                    min_arrival_time = min(min_arrival_time, dp[i - 1][p] + dist[p][j]);
                }
            }

            if (min_arrival_time != INF) {
                long long finish_time = min_arrival_time + t[i - 1];
                if (finish_time <= c[j - 1]) {
                    dp[i][j] = finish_time;
                }
            }
        }
    }

    // --- Find Result ---
    int max_pints = 0;
    for (int i = r_max; i >= 1; --i) {
        for (int j = 1; j <= k; ++j) {
            if (dp[i][j] != INF) {
                max_pints = i;
                goto end_loops;
            }
        }
    }

end_loops:
    cout << max_pints << endl;

    return 0;
}