#include<bits/stdc++.h>
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
#define pii pair<ll,ll>
#define rep(i,a,b) for(ll i=(a);i<=(b);++i)
#define per(i,a,b) for(ll i=(a);i>=(b);--i)
using namespace std;
bool Mbe;
ll read(){
    ll x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
void write(ll x){
    if(x<0)putchar('-'),x=-x;
    if(x>9)write(x/10);
    putchar(x%10+'0');
}
#define PQ priority_queue<array<ll,3>,vector<array<ll,3> >,greater<array<ll,3> > >
const ll N=6e5+9;
ll n,m,W[N],A[N],B[N],S[N],rS[N],fa[N],sz[N],sum[N],tag[N],psh[N];
PQ q[N];
priority_queue<ll,vector<ll>,greater<ll> >Q;
ll find(ll x){
    return fa[x]==x?x:fa[x]=find(fa[x]);
}
void Remake(ll y){
    while(!q[y].empty()&&q[y].top()[0]-tag[y]<=0){
        array<ll,3> p=q[y].top();q[y].pop();
        ll id=p[2],fx=find(A[id]),fy=find(B[id]);
        if(psh[id])continue;
        if(sum[fx]+sum[fy]>=S[id]){
            Q.push(id),psh[id]=1;
            continue;
        }
        if(rS[id]!=p[1]||fx==fy)continue;
        ll mid=(S[id]-sum[fx]-sum[fy]+1)/2;
        q[fx].push({mid+tag[fx],mid,id});
        q[fy].push({mid+tag[fy],mid,id});
        rS[id]=mid;
    }
}
bool Unite(ll x,ll y){
    x=find(x),y=find(y);
    if(x==y)return 0;
    if(sz[x]>sz[y])swap(x,y);
    tag[y]+=sum[x];
    while(!q[x].empty()){
        array<ll,3> p=q[x].top();q[x].pop();
        q[y].push({p[0]-tag[x]+tag[y],p[1],p[2]});
    }
    PQ().swap(q[x]),sz[y]+=sz[x],sum[y]+=sum[x],fa[x]=y,tag[x]=0;
    return Remake(y),1;
}
bool Med;
int main(){
    cerr<<fabs(&Med-&Mbe)/1048576.0<<"MB\n";
    n=read(),m=read();
    rep(i,1,n)W[i]=read(),fa[i]=i,sz[i]=1,tag[i]=sum[i]=W[i];
    rep(i,1,m)A[i]=read(),B[i]=read(),S[i]=read(),rS[i]=S[i];
    rep(i,1,m){
        if(W[A[i]]+W[B[i]]>=S[i])Q.push(i);
        else q[A[i]].push({(S[i]+1)/2,S[i],i}),q[B[i]].push({(S[i]+1)/2,S[i],i});
    }
    vector<ll>ans;
    while(!Q.empty()){
        ll i=Q.top();Q.pop();
        if(Unite(A[i],B[i]))ans.push_back(i);
    }
    write(ans.size()),putchar('\n');
    for(ll x:ans)write(x),putchar(' ');
    putchar('\n');
    cerr<<"\n"<<clock()*1.0/CLOCKS_PER_SEC*1000<<"ms\n";
    return 0;
}