# include <bits/stdc++.h>
using namespace std;
using ll=long long;
constexpr ll INF=1e18;
int rev[600010],head[1010],nxt[600010],tot=1;
bool visV[1010],visE[600010];
tuple<int,int,int> ans[200010];
mt19937 rnd;
struct Edge
{
	int v,c,f;
	Edge(){}
	Edge(int v,int c):v(v),c(c),f(0){}
}edge[600010];
void addedge(int u,int v,int c)
{
	nxt[++tot]=head[u];
	edge[tot]=Edge(v,c);
	head[u]=tot;
}
void addE(int u,int v,int c){addedge(u,v,c);addedge(v,u,0);}
ll dfs(int u,int t,ll minn)
{
	if(u==t || !minn) return minn;
	visV[u]=1;
	ll ans=0;
	vector<int> id;
	for(int i=head[u];i;i=nxt[i]) id.push_back(i);
	shuffle(id.begin(),id.end(),rnd);
	for(int i:id)
	{
		int v=edge[i].v,c=edge[i].c,f=edge[i].f;
		if(visV[v] || c<=f) continue;
		visE[i]=1;
		ll x=dfs(v,t,min(minn,ll(visE[rev[i]]?(c-f)/2:c-f)));
		visE[i]=0;
		edge[i].f+=x;edge[i^1].f-=x;
		edge[rev[i]].f+=x;edge[rev[i]^1].f-=x;
		ans+=x;minn-=x;
		if(!minn) break;
	}
	visV[u]=0;
	return ans;
}
int main()
{
	int n,m,u,v,c,s,t;
	ll sum=0;
	cin>>n>>m;s=n+n+1;t=s+1;
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&c);sum+=c;
		rev[tot+1]=tot+3;rev[tot+2]=tot+4;
		rev[tot+3]=tot+1;rev[tot+4]=tot+2;
		addE(s,i,c);addE(i+n,t,c);
	}
	for(int i=0;i<m;i++)
	{
		scanf("%d%d%d",&u,&v,&c);
		rev[tot+1]=tot+3;rev[tot+2]=tot+4;
		rev[tot+3]=tot+1;rev[tot+4]=tot+2;
		addE(u,v+n,c);addE(v,u+n,c);
	}
	sum/=2;
	while(sum) sum-=dfs(s,t,INF);
	tot=0;
	for(int u=1;u<=n;u++)
		for(int i=head[u];i;i=nxt[i])
			if((v=edge[i].v-n)<u && edge[i].f>0)
				ans[++tot]=make_tuple(u,v,edge[i].f);
	cout<<tot<<endl;
	for(int i=1;i<=tot;i++) printf("%d %d %d\n",get<0>(ans[i]),get<1>(ans[i]),get<2>(ans[i]));
	return 0;
}