#include <bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f3f3f3f3f
#define N 400010
#define ll long long
#define fir first
#define sec second
#define make make_pair
//#define int long long

char buf[1<<21], *p1=buf, *p2=buf;
#define getchar() (p1==p2&&(p2=(p1=buf)+fread(buf, 1, 1<<21, stdin)), p1==p2?EOF:*p1++)
inline int read() {
	int ans=0, f=1; char c=getchar();
	while (!isdigit(c)) {if (c=='-') f=-f; c=getchar();}
	while (isdigit(c)) {ans=(ans<<3)+(ans<<1)+(c^48); c=getchar();}
	return ans*f;
}

int n, m;
int col[N], head[N], size=1, fa[N];
bool able[N];
struct edge{int to, next; ll val; bool liv;}e[N<<1];
inline void add(int s, int t, ll w) {e[++size].to=t; e[size].val=w; e[size].next=head[s]; head[s]=size;}
inline int find(int p) {return fa[p]==p?p:fa[p]=find(fa[p]);}

namespace force{
	ll ans=INF, mdis[N], dis[N];
	bool vis[N];
	priority_queue<pair<ll, int>> q;
	void dij(int s) {
		// cout<<"dij: "<<s<<endl;
		memset(dis, 0x3f, sizeof(dis));
		memset(vis, 0, sizeof(vis));
		while (q.size()) q.pop();
		dis[s]=0; q.push(make(0, s));
		pair<ll, int> u;
		while (q.size()) {
			u=q.top(); q.pop();
			if (vis[u.sec]) continue;
			vis[u.sec]=1;
			for (int i=head[u.sec],v; ~i; i=e[i].next) if (e[i].liv) {
				v = e[i].to;
				if (dis[u.sec]+e[i].val < dis[v]) {
					dis[v] = dis[u.sec]+e[i].val;
					q.push(make(-dis[v], v));
				}
			}
		}
		// cout<<"dis: "; for (int i=1; i<=n; ++i) cout<<dis[i]<<' '; cout<<endl;
	}
	void init() {
		// cout<<"init"<<endl;
		memset(mdis, 0x3f, sizeof(mdis));
		for (int i=2; i<=m*2+1; ++i) e[i].liv=1;
		for (int i=1; i<=n; ++i) if (!col[i]) {
			dij(i);
			for (int j=1; j<=n; ++j) if (col[j]) mdis[i]=min(mdis[i], dis[j]);
		}
		// cout<<"mdis: "; for (int i=1; i<=n; ++i) cout<<mdis[i]<<' '; cout<<endl;
	}
	bool check() {
		// cout<<"check"<<endl;
		for (int i=1; i<=n; ++i) if (!col[i]) {
			// cout<<"i: "<<i<<endl;
			dij(i);
			ll minn=INF;
			for (int j=1; j<=n; ++j) if (col[j]) minn=min(minn, dis[j]);
			if (minn!=mdis[i]) return 0;
		}
		return 1;
	}
	void solve() {
		init();
		int lim=1<<m;
		for (int s=0; s<lim; ++s) {
			ll sum=0;
			for (int i=0,t; i<m; ++i) {
				t=(i+1)<<1;
				if (s&(1<<i)) {
					e[t].liv=e[t^1].liv=1;
					sum+=e[t].val;
				}
				else {
					e[t].liv=e[t^1].liv=0;
				}
			}
			if (sum<ans && check()) ans=min(ans, sum);
		}
		printf("%lld\n", ans);
		exit(0);
	}
}

namespace task1{
	ll ans, dis[N];
	int sta[N], top, back[N];
	bool vis[N], insta[N], keep[N];
	priority_queue<pair<ll, int>> q;
	void dij(int s) {
		while (q.size()) q.pop();
		dis[s]=0; q.push(make(0, s));
		sta[++top]=s; insta[s]=1;
		pair<ll, int> u;
		while (q.size()) {
			u=q.top(); q.pop();
			if (vis[u.sec]) continue;
			vis[u.sec]=1;
			if (col[u.sec]) {
				int now=u.sec;
				do {
					keep[back[now]]=keep[back[now]^1]=1;
					now=e[back[now]].to;
				} while (now!=s);
				while (top) {
					dis[sta[top]]=INF; vis[sta[top]]=0; insta[sta[top]]=0; back[sta[top]]=0;
					--top;
				}
				return ;
			}
			for (int i=head[u.sec],v; ~i; i=e[i].next) {
				v = e[i].to;
				if (dis[u.sec]+e[i].val < dis[v]) {
					dis[v] = dis[u.sec]+e[i].val; back[v]=i^1;
					if (!insta[v]) {sta[++top]=v; insta[v]=1;}
					q.push(make(-dis[v], v));
				}
			}
		}
		puts("error");
	}
	void solve() {
		memset(dis, 0x3f, sizeof(dis));
		for (int i=1; i<=n; ++i) if (!col[i]) dij(i);
		for (int i=2; i<=m*2; i+=2) if (keep[i]) ans+=e[i].val;
		printf("%lld\n", ans);
		exit(0);
	}
}

signed main()
{
	freopen("minimum.in", "r", stdin);
	freopen("minimum.out", "w", stdout);

	memset(head, -1, sizeof(head));
	n=read(); m=read();
	for (int i=1; i<=n; ++i) col[i]=read(), fa[i]=i, able[i]=(col[i]==1)?1:0;
	for (int i=1,x,y,z; i<=m; ++i) {
		x=read(); y=read(); z=read();
		add(x, y, z); add(y, x, z);
		int f1=find(x), f2=find(y);
		if (f1!=f2) {fa[f1]=f2; able[f2]|=able[f1];}
	}
	for (int i=1; i<=n; ++i) if (!col[i] && !able[find(i)]) {puts("impossible"); return 0;}
	task1::solve();

	return 0;
}