#include <bits/stdc++.h>
using namespace std;
const int N = 4e5 + 5; 
const int INF = 1e9 + 5; 

int n, m; 
int a[N], fa[N], use[N]; 
vector<int> ans; 
int find(int x) { return fa[x] == x ? x : fa[x] = find(fa[x]); }

struct Edge {
    int u, v, c; 
} e[N]; 

priority_queue<int, vector<int>, greater<int>> todo; 
#define pii pair<int, int>
priority_queue<pii, vector<pii>, greater<pii>> q[N]; 

inline void add(int i) {
    if (use[i]) return; 

    int x = find(e[i].u), y = find(e[i].v); 
    if (x == y) return; 

    if (a[x] + a[y] >= e[i].c) return todo.push(i), void(); 

    q[x].emplace((e[i].c - a[x] - a[y] + 1) / 2, i); 
    q[y].emplace((e[i].c - a[y] - a[x] + 1) / 2, i); 
}

inline void merge(int i) {
    int u = find(e[i].u), v = find(e[i].v); 
    if (u == v) return; ans.push_back(i); use[i] = 1; 

    if (q[u].size() > q[v].size()) swap(u, v); 
    fa[u] = v; a[v] = min(INF, a[u] + a[v]); 

    while (q[u].size()) {
        auto it = q[u].top(); q[u].pop(); 
        if (a[v] >= it.first) add(it.second); 
        else q[v].push(it); 
    }
    while (q[v].size()) {
        auto it = q[v].top(); q[v].pop(); 
        if (a[v] >= it.first) add(it.second); 
        else { q[v].push(it); break; }
    }
}

int main(void) {
    ios::sync_with_stdio(0); 
    cin >> n >> m; 
    for (int i = 1; i <= n; ++i) cin >> a[i], fa[i] = i; 
    for (int i = 1; i <= m; ++i) cin >> e[i].u >> e[i].v >> e[i].c, add(i); 
    while (!todo.empty()) {
        int i = todo.top(); todo.pop(); 
        merge(i); 
    }
    cout << ans.size() << "\n"; 
    for (int i : ans) cout << i << " "; cout << "\n"; 
    return 0;
}