#include <iostream>
#include <queue>
using namespace std;

const int MAX = 1000;
const int INF = 10000000;

class Edge
{
public:
	int cost;
	int dest;
	Edge *next;

	Edge(int c, int d, Edge *n=0) : cost(c), dest(d), next(n)
	{}
};

class Vertex
{
public:
	string name;
	int dist;
	int len;
	int prev;
	bool visited;
	Edge *adj;

	Vertex(string s="") : name(s), dist(INF), len(MAX), prev(-1), visited(false), adj(0)
	{}
} vertices[MAX];
int nVerts = 0;

void printGraph()
{
	for(int i=0; i<nVerts; i++) {
		cout << vertices[i].name << ":";
		for(Edge *j=vertices[i].adj; j != 0; j = j->next) {
			cout << " " << vertices[j->dest].name;
		}
		cout << endl;
	}
}

int getVertex(string s)
{
	for(int i=0; i<nVerts; i++) {
		if (vertices[i].name == s)
			return i;
	}
	vertices[nVerts].name = s;
	return nVerts++;
}

void addEdge(string src, string dst, int cost)
{
	int i1 = getVertex(src);
	int i2 = getVertex(dst);
	vertices[i1].adj = new Edge(cost, i2, vertices[i1].adj);
}

void version3()
{
	queue<int> q;
	vertices[0].dist = vertices[0].len = 0;
	q.push(0);
	while (!q.empty()) {
		int i = q.front();
		q.pop();
		if (vertices[i].visited)
			continue;
		vertices[i].visited = true;
		int len = vertices[i].len;
		int dist = vertices[i].dist;
		for(Edge *p = vertices[i].adj; p != 0; p = p->next) {
			int j = p->dest;
			if (vertices[j].len >= len+1 && vertices[j].dist >= p->cost) {
				if (vertices[j].len == MAX) {
					q.push(j);
//cout << "inserting " << vertices[j].name << " onto q" << endl;
				}
//cout << "updating " << vertices[j].name << ": " << len+1 << ',' << dist+p->cost << ',' << vertices[i].name << endl;
				vertices[j].len = len+1;
				vertices[j].dist = p->cost;
				vertices[j].prev = i;
			}
		}
	}
}

int main()
{
	int n, m;
	string targets[MAX];
	
	cin >> n >> m;
	getVertex("English");
	for(int i=0; i<n; i++) {
		cin >> targets[i];
		getVertex(targets[i]);
	}
	for(int i=0; i<m; i++) {
		string s1, s2;
		int cost;
		cin >> s1 >> s2 >> cost;
		addEdge(s1, s2, cost);
		addEdge(s2, s1, cost);
	}

	version3();
	int cost = 0;
	bool noSol = false;
	for(int i=0; i<n; i++) {
		int j = getVertex(targets[i]);
		if (vertices[j].dist == INF) {
			noSol = true;
			break;
		}
		cost += vertices[j].dist;
	}
	if (noSol)
		cout << "Impossible" << endl;
	else
		cout << cost << endl;
/*
for(int i=1; i<nVerts; i++) {
cout << vertices[i].name << "," << vertices[i].dist << ',' << vertices[vertices[i].prev].name << endl;
}
/**/
}