#include<bits/stdc++.h>
#define ll long long
#define db double
#define ull unsigned long long
#define pb push_back
#define pii pair<int, int>
#define FR first
#define SE second
using namespace std;
inline int read() {
  int x = 0; bool op = false;
  char c = getchar();
  while(!isdigit(c))op |= (c == '-'), c = getchar();
  while(isdigit(c))x = (x << 1) + (x << 3) + (c ^ 48), c = getchar();
  return op ? -x : x;
}
const int N = 3e5 + 10;
const int Mx = 1e6;
int n, m;
int a[N], f[N], sum[N], vis[N], le[N], sz[N];
struct Edge {int u, v, w, lu, lv;};
Edge e[N];
int tot;
struct Node {
  int ls, rs, d;
  pii w;
}nd[N * 30];
int New(pii x) {
  int cur = ++tot;
  nd[cur] = {0, 0, 1, x};
  return cur;
}
int merge(int x, int y) {
  if(!x || !y)return x + y;
  if(nd[x].w.FR > nd[y].w.FR)swap(x, y);
  nd[x].rs = merge(nd[x].rs, y);
  if(nd[nd[x].ls].d < nd[nd[x].rs].d)swap(nd[x].ls, nd[x].rs);
  nd[x].d = nd[nd[x].rs].d + 1;
  return x;
}
int st[N], del[N];
// priority_queue<pii, vector<pii>, greater<pii> > st[N], del[N];
int find(int x) {return f[x] == x ? x : f[x] = find(f[x]);}
int pop(int x) {return merge(nd[x].ls, nd[x].rs);}
signed main() {
  n = read(); m = read();
  for(int i = 1; i <= n; i++)a[i] = read();
  priority_queue<int, vector<int>, greater<int> > q;
  for(int i = 1; i <= n; i++)f[i] = i;
  for(int i = 1; i <= m; i++) {
    int u = read(), v = read(), w = read();
    e[i] = {u, v, w};
    if(a[u] + a[v] >= w)q.push(i);
    else {
      int val = (w - a[u] - a[v] + 1) / 2;
      st[u] = merge(st[u], New({e[i].lu = a[u] + val, i}));
      st[v] = merge(st[v], New({e[i].lv = a[v] + val, i}));
    }
  }
  vector<int> ans;
  auto flush = [&](int u) {
    while(st[u] && del[u] && nd[st[u]].w == nd[del[u]].w)
      st[u] = pop(st[u]), del[u] = pop(del[u]);
    return ;
  };
  auto unionn = [&](int u, int v) {
    u = find(u); v = find(v);
    if(sz[u] < sz[v])swap(u, v);
    f[v] = u; a[u] = min(a[u] + a[v], Mx);
    st[u] = merge(st[u], st[v]);
    del[u] = merge(del[u], del[v]);
    // cerr << u << ' ' << v << endl;
    flush(u);
    while(st[u] && nd[st[u]].w.FR <= a[u]) {
      int id = nd[st[u]].w.SE;
      int x = find(e[id].u), y = find(e[id].v);
      // cerr << e[id].u << ' ' << e[id].v << ' ' << x << ' ' << y << endl;
      // cerr << "why:" << u << ' ' << x << ' ' << y << ' ' << nd[st[u]].w.FR << ' ' << nd[del[u]].w.FR << endl;
      del[x] = merge(del[x], New({e[id].lu, id}));
      del[y] = merge(del[y], New({e[id].lv, id}));
      flush(u);
      if(x == y)continue;
      if(a[x] + a[y] >= e[id].w)q.push(id);
      else {
        int val = (e[id].w - a[x] - a[y] + 1) / 2;
        st[x] = merge(st[x], New({e[id].lu = a[x] + val, id}));
        st[y] = merge(st[y], New({e[id].lv = a[y] + val, id}));
      }
    }
    return ;
  };
  while(q.empty() == false) {
    int id = q.top(); q.pop();
    if(find(e[id].u) == find(e[id].v))continue;
    ans.pb(id); 
    unionn(e[id].u, e[id].v);
  }
  printf("%lu\n", ans.size());
  for(int x : ans)printf("%d ", x); putchar('\n');
  return 0;
}