#include <string.h>
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;

using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
template <typename T> using vc = vector<T>;
template <typename T> using vvc = vector<vector<T>>;
template <typename T> using vvvc = vector<vector<vector<T>>>;
template<class T> using pq = priority_queue<T,vector<T>,greater<T>>;
template <class T, class S> inline bool chmax(T &a, const S &b) { return (a < b ? a = b, 1 : 0); }
template <class T, class S> inline bool chmin(T &a, const S &b) { return (a > b ? a = b, 1 : 0); }

int dx4[] = {1,0,-1,0};
int dy4[] = {0,1,0,-1};

#define overload5(a, b, c, d, e, name, ...) name
#define overload4(a, b, c, d, name, ...) name
#define REP0(n) for(ll jidlsjf = 0; jidlsjf < n; ++jidlsjf)
#define REP1(i, n) for(ll i = 0; i < (n); ++i)
#define REP2(i, a, b) for(ll i = (a); i < (b); ++i)
#define REP3(i, a, b, c) for(ll i = (a); i < (b); i += (c))
#define rep(...) overload4(__VA_ARGS__, REP3, REP2, REP1, REP0)(__VA_ARGS__)
#define per0(n) for(int jidlsjf = 0; jidlsjf < (n); ++jidlsjf)
#define per1(i, n) for(ll i = (n)-1; i >= 0; --i)
#define per2(i, a, b) for(ll i = (a)-1; i >= b; --i)
#define per3(i, a, b, c) for(ll i = (a)-1; i >= (b); i -= (c))
#define per(...) overload4(__VA_ARGS__, per3, per2, per1, per0)(__VA_ARGS__)
#define fi first
#define se second
#define pb push_back
#define ppb pop_back
#define ppf pop_front
#define drop(s) cout << #s << endl, exit(0)
#define si(c) (int)(c).size()
#define lb(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define lbg(c, x) distance((c).begin(), lower_bound(all(c), (x), greater{}))
#define ub(c, x) distance((c).begin(), upper_bound(all(c), (x)))
#define ubg(c, x) distance((c).begin(), upper_bound(all(c), (x), greater{}))
#define rng(v, l, r) v.begin() + (l), v.begin() + (r)
#define all(c) c.begin(), c.end()
#define rall(c) c.rbegin(), c.rend()
#define SORT(v) sort(all(v))
#define REV(v) reverse(all(v))
#define UNIQUE(x) SORT(x), x.erase(unique(all(x)), x.end())
#define MIN(v) *min_element(all(v))
#define MAX(v) *max_element(all(v))
#define overload2(_1, _2, name, ...) name
#define vec(type, name, ...) vector<type> name(__VA_ARGS__)
#define vv(type, name, h, ...) vector<vector<type>> name(h, vector<type>(__VA_ARGS__))
#define vvv(type, name, h, w, ...) vector<vector<vector<type>>> name(h, vector<vector<type>>(w, vector<type>(__VA_ARGS__)))

ll inf = 1001001001001001001;

template< typename flow_t >
struct Dinic {
    const flow_t INF;
    
    struct edge {
        int to;
        flow_t cap;
        int rev;
        bool isrev;
        int idx;
    };
    
    vector< vector< edge > > graph;
    vector< int > min_cost, iter;
    
    Dinic(int V) : INF(numeric_limits< flow_t >::max()), graph(V) {}
    
    void add_edge(int from, int to, flow_t cap, int idx = -1) {
        graph[from].emplace_back((edge) {to, cap, (int) graph[to].size(), false, idx});
        graph[to].emplace_back((edge) {from, 0, (int) graph[from].size() - 1, true, idx});
    }
    
    bool bfs(int s, int t) {
        min_cost.assign(graph.size(), -1);
        queue< int > que;
        min_cost[s] = 0;
        que.push(s);
        while(!que.empty() && min_cost[t] == -1) {
            int p = que.front();
            que.pop();
            for(auto &e : graph[p]) {
                if(e.cap > 0 && min_cost[e.to] == -1) {
                    min_cost[e.to] = min_cost[p] + 1;
                    que.push(e.to);
                }
            }
        }
        return min_cost[t] != -1;
    }
    
    flow_t dfs(int idx, const int t, flow_t flow) {
        if(idx == t) return flow;
        for(int &i = iter[idx]; i < graph[idx].size(); i++) {
            edge &e = graph[idx][i];
            if(e.cap > 0 && min_cost[idx] < min_cost[e.to]) {
                flow_t d = dfs(e.to, t, min(flow, e.cap));
                if(d > 0) {
                    e.cap -= d;
                    graph[e.to][e.rev].cap += d;
                    return d;
                }
            }
        }
        return 0;
    }
    
    flow_t max_flow(int s, int t) {
        flow_t flow = 0;
        while(bfs(s, t)) {
            iter.assign(graph.size(), 0);
            flow_t f = 0;
            while((f = dfs(s, t, INF)) > 0) flow += f;
        }
        return flow;
    }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n,m;
    cin >> n >> m;
    vc<int>a(n-1),b(n),c(n-1);
    Dinic<int>flow(n+1);
    int S = 0,T = n;
    rep(i,n-1) {
        cin >> a[i];
        flow.add_edge(S,i+1,a[i]);
    }
    rep(i,n) {
        cin >> b[i];
        if(i == 0) {
            flow.add_edge(i+1,T,b[i]);
            continue;
        }
        if(i+1 == n) {
            flow.add_edge(S,i,b[i]);
            continue;
        }
        flow.add_edge(i,i+1,b[i]);
        flow.add_edge(i+1,i,b[i]);
    }
    rep(i,n-1) {
        cin >> c[i];
        flow.add_edge(i+1,T,c[i]);
    }
    rep(i,m) {
        int U,V,C;
        cin >> U >> V >> C;
        flow.add_edge(V,U,C);
    }
    cout << flow.max_flow(S,T) << "\n";
}