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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m, F, B, W;
    cin >> n >> m;
    vector<int> L(n + 2);
    for(int i = 1; i <= n; i++) cin >> L[i];
    L.back() = (1ll << 31) - 1, L[0] = -(1 << 30);
    auto f = [&](int pos){
        int p = lower_bound(L.begin(), L.end(), pos) - L.begin();
        return min(L[p] - pos, pos - L[p - 1]);
    };
    ll ans = 0;
    while(m--){
        cin >> F >> B >> W;
        ans += max(B, W - f(F));
    }
    cout << ans << '\n';
}