#include <fstream>
#include <vector>
#include <queue>
#include <bitset>
using namespace std;
string file = "apm";
ifstream cin (file + ".in");
ofstream cout (file + ".out");
const int N = 2e5;
struct muchie{
    int vf;
    int cost;
    bool operator < (const muchie &y) const
    {
        return cost > y.cost;
    }
};

vector <muchie> a[N+1];
bitset <N+1> in_t;
int n,predecesor[N+1];
int prim()
{
    priority_queue <muchie> h;
    h.push({1,0});
    int cost_total = 0;
    while (!h.empty())
    {
        int x = h.top().vf, y = h.top().cost;
        h.pop();
        if (in_t[x])
        {
            continue;
        }
        cost_total += y;
        in_t[x] = 1;
        for (auto e : a[x])
        {
            int c = e.cost, y = e.vf;
            if (!in_t[y])
            {
                predecesor[y] = x;
                h.push({y,c});

            }
        }
    }
    return cost_total;
}

int main ()
{
    int m,x,y,z;
    cin >> n >> m;
    while (m--)
    {
        cin >> x >> y >> z;
        a[x].push_back({y,z});
        a[y].push_back({x,z});
    }
    cout << prim() << '\n' << n-1;
    for (int i=2; i<=n; i++)
    {
        cout << '\n' << predecesor[i] << ' ' << i;
    }
}