#include <iostream>
#include <vector>
#include <queue>

using namespace std;
const int INF = 1e9;
vector<vector<pair<int, int>>> adj;
vector<int> dist;
vector<bool> vis;
vector<vector<int>> path;
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
bool lessthan(vector<int> a, vector<int> b) {
    for(int i = 0; i < min(a.size(), b.size()); i++) {
        if(a[i] < b[i]) return true;
        if(a[i] > b[i]) return false;
    }
    return a.size() < b.size();
}

int main() {
    int n, m;
    cin >> n >> m;
    adj.resize(n + 1);
    dist.resize(n + 1, INF);
    vis.resize(n + 1, false);
    path.resize(n + 1);
    for(int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        adj[a].push_back(make_pair(b, c));
    }

    dist[0] = 0;
    path[0].push_back(0);
    pq.push(make_pair(0, 0));
    while(!pq.empty()) {
        int u = pq.top().second;
        pq.pop();
        if(vis[u]) continue;
        vis[u] = true;
        for(auto [v, w] : adj[u]) {
            if(dist[v] > dist[u] + w) {
                dist[v] = dist[u] + w;
                path[v] = path[u];
                path[v].push_back(v);
                pq.push(make_pair(dist[v], v));
            }
            else if(dist[v] == dist[u] + w) {
                vector<int> new_path = path[u];
                new_path.push_back(v);
                if(path[v].empty() || path[v].size() > new_path.size() || 
                   (path[v].size() == new_path.size() && lessthan(new_path, path[v]))) {
                    path[v] = new_path;
                    pq.push(make_pair(dist[v], v));
                }
            }
        }
    }
    
    for(int i = 1; i < n; i++) {
        if(dist[i] != INF && !path[i].empty()) {
            for(int j = 0; j < path[i].size(); j++) {
                if(j > 0) cout << "->";
                cout << path[i][j];
            }
            cout << endl;
        }
    }
    
    return 0;
}