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

typedef long long ll;
const int maxn = 1005;
const int maxm = 20005;
const ll inf = 2e13;
const ll INF = 4e18;

int rv[2][maxn], cv[maxn];

int s, t;
struct edge
{
	int v, next;
	ll flow;
}e[2 * maxm];
int head[maxn], tot;

inline void addedge(int u, int v, ll c)
{
	e[++tot] = (edge){v, head[u], c}; head[u] = tot;
	e[++tot] = (edge){u, head[v], 0}; head[v] = tot;
}

int d[maxn], cur[maxn];
bool bfs()
{
    for (int i = s; i <= t; i++) d[i] = 0, cur[i] = head[i];
    queue<int> q; q.push(s), d[s] = 1;
    while (q.size())
    {
        int u = q.front(); q.pop();
        for (int i = head[u]; ~i; i = e[i].next)
        {
            int v = e[i].v;
            if (!d[v] && e[i].flow)
            {
                d[v] = d[u] + 1;
                if (v == t) return true;
                q.push(v);
            }
        }
    }
    return false;
}

ll dfs(int u, ll flow)
{
    if (u == t || !flow) return flow;
    ll rest = flow;
    for (int &i = cur[u]; ~i; i = e[i].next)
    {
        int v = e[i].v;
        if (d[v] == d[u] + 1 && e[i].flow)
        {
            ll k = dfs(v, min(rest, e[i].flow));
            if (!k) d[v] = 0;
            e[i].flow -= k, e[i ^ 1].flow += k;
            if (!(rest -= k)) break;
        }
    }
    return flow - rest;
}

ll Dinic()
{
    ll maxflow = 0;
    while (bfs()) maxflow += dfs(s, INF);
    return maxflow;
}

int main()
{
    ios::sync_with_stdio(false), cin.tie(0);
    memset(head, -1, sizeof(head)), tot = -1;

    int n, m; cin >> n >> m;
    for (int i = 1; i < n; i++) cin >> rv[0][i];
    for (int i = 1; i <= n; i++) cin >> cv[i];
    for (int i = 1; i < n; i++) cin >> rv[1][i];
    if (n == 1) return cout << cv[1], 0;

    s = 0, t = 2 * n - 1;
    for (int i = 1; i < n; i++)
    {
        addedge(s, i, inf + rv[1][i] + (i == 1 ? cv[1] : 0));
        addedge(i + n - 1, t, inf + rv[0][i] + (i == n - 1 ? cv[n] : 0));
        addedge(i, i + n - 1, INF);
    }
    for (int i = 1; i < n - 1; i++) addedge(i, i + n, cv[i + 1]), addedge(i + n - 1, i + 1, cv[i + 1]);
    for (int i = 1; i <= m; i++)
    {
        int x, y, val; cin >> x >> y >> val;
        addedge(x, y + n - 1, val);
    }
    cout << Dinic() - inf * (n - 1);
    return 0;
}