#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <tuple>
#include <set>

using namespace std;

class DSU {
public:
    vector<int> parent;
    vector<int> height;

    DSU(int n) {
        parent.resize(n);
        for (int i = 0; i < n; ++i) {
            parent[i] = i;
        }
        height.assign(n, 0);
    }

    int findRoot(int v) {
        if (v == parent[v]) {
            return v;
        }
        int ans = findRoot(parent[v]);
        parent[v] = ans;
        return ans;
    }

    void Union(int v1, int v2) {
        if (height[v1] >= height[v2]) {
            parent[v2] = v1;
            height[v1] = max(height[v1], height[v2] + 1);
        } else {
            parent[v1] = v2;
            height[v2] = max(height[v2], height[v1] + 1);
        }
    }


};

int main() {
    int n, m;
    cin >> n >> m;
    DSU graph(n);
    vector<pair<pair<int, int>, pair<int, int>>> edges;
    vector<int> edge_weight;
    for (size_t i = 0; i < m; ++i) {
        int v1, v2, w;
        cin >> v1 >> v2 >> w, --v1, --v2;
        edges.emplace_back(make_pair(w, i), make_pair(v1, v2));
        edge_weight.emplace_back(w);
    }
    int p5, q5, p6, q6;
    cin >> p5 >> q5 >> p6 >> q6;
    sort(edges.begin(), edges.end());
    int edge_cnt = 0;
    vector<int> used_edges;
    vector<int> pack(q5 + 1, -1);
    int max_possible = 0;
    //weight.first - weight, weight.second - index
    for (auto [weight, coord]: edges) {
        if (graph.findRoot(coord.first) != graph.findRoot(coord.second)) {
            graph.Union(graph.findRoot(coord.first), graph.findRoot(coord.second));
            ++edge_cnt;
            used_edges.emplace_back(weight.second);
            for (int i = q5; i > 0; --i) {
                if (pack[i] > -1 && i + weight.first <= q5) {
                    pack[i + weight.first] = weight.second;
                    max_possible = max(i + weight.first, max_possible);
                } else if (pack[i] == -1) {
                    pack[i] = weight.second;
                    max_possible = max(i, max_possible);
                }
            }
        }
    }
    if (edge_cnt < n - 1) {
        cout << "impossible";
    } else {
        set<int> cheap;
        while (max_possible > 0) {
            cheap.emplace(pack[max_possible]);
            max_possible -= edge_weight[pack[max_possible]];
        }
        int total_cost = 0;
        for (auto edge: used_edges) {
            if (!cheap.contains(edge)) {
                q6 -= edge_weight[edge];
                total_cost += edge_weight[edge] * p6;
            } else {
                total_cost += edge_weight[edge] * p5;
            }
        }
        if (q6 < 0){
            cout << "impossible";
        } else {
            cout << total_cost << '\n';
            for (auto edge: used_edges){
                if (cheap.contains(edge)){
                    cout << edge + 1 << " 5\n";
                } else {
                    cout << edge + 1 << " 6\n";
                }
            }
        }
    }

    return 0;
};