#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e4+10;
const int maxm = 100000+10;
const int INF = 0x3f3f3f3f;
int s, t, n, m;
struct Edge{
    int v, cost, cap, next, flow;
}edge[maxm];
int head[maxn];
int pre[maxn];//记录的是哪一条边的编号
int tot;
int dis[maxn];
bool vis[maxn];
void init(){
    memset(pre, -1, sizeof(pre));
    memset(head, -1, sizeof(head));
    tot = 0;
}
void add_edge(int u, int v, int weight, int price){
    edge[tot].v = v;
    edge[tot].cost = price;
    edge[tot].cap = weight;
    edge[tot].flow = 0;
    edge[tot].next = head[u];
    head[u] = tot++;
    edge[tot].v = u;
    edge[tot].cost = -1*price;
    edge[tot].cap = 0;
    edge[tot].flow = 0;
    edge[tot].next = head[v];
    head[v] = tot++;
}
bool SPFA(int s, int t){
    for(int i=0; i<maxn; i++) dis[i] = INF;
    dis[s] = 0;
    memset(vis, 0, sizeof(vis));
    memset(pre, -1, sizeof(pre));
    queue<int> q;
    while(!q.empty()) q.pop();
    q.push(s);
    vis[s] = true;
    while(!q.empty()){
        int u = q.front();
        q.pop();
        vis[u] = false;
        for(int i=head[u]; ~i; i=edge[i].next){
            int v = edge[i].v;
            if(edge[i].cap>edge[i].flow && dis[v]>dis[u]+edge[i].cost){
                dis[v] = dis[u]+edge[i].cost;
                pre[v] = i;
                if(!vis[v]){
                    q.push(v);
                    vis[v] = true;
                }
            }
        }
    }
    if(pre[t] == -1) return false;
    return true;
}
int min_cost_max_flow(int s, int t, int &min_cost){
    int flow = 0;
    while(SPFA(s, t)){
        int Min = INF;
        for(int i = pre[t]; ~i; i = pre[edge[i^1].v]){
            if(Min>edge[i].cap-edge[i].flow){
                Min = edge[i].cap - edge[i].flow;
            }
        }
        for(int i=pre[t]; ~i; i = pre[edge[i^1].v]){
            //cout<<edge[i^1].v<<" ";
            edge[i].flow += Min;
            edge[i^1].flow -= Min;
            min_cost += edge[i].cost*Min;
        }
        flow += Min;
    }
    return flow;
}
int a[maxn];
int main(){
    ios::sync_with_stdio(false);
    init();
    int x, y,z;
     scanf("%d%d" , &n , &m) , s = 0 , t = n + 2;
    for(int i = 1 ; i <= n ; i ++ ) scanf("%d" , &a[i]) , add_edge(i + 1 , i , INF , 0);
    for(int i = 1 ; i <= m ; i ++ ) scanf("%d%d%d" , &x , &y , &z) , add_edge(x , y + 1 , INF, z);
    for(int i = 1 ; i <= n + 1 ; i ++ )
    {
        if(a[i] - a[i - 1] > 0) add_edge(s , i , a[i] - a[i - 1] , 0);
        if(a[i] - a[i - 1] < 0) add_edge(i , t , a[i - 1] - a[i] , 0);
    }
    int ans=0;
    //cout<<ans<<endl;
    min_cost_max_flow(s, t, ans);
    printf("%d\n" , ans);
    return 0;
}