#include<bits/stdc++.h>
using namespace std;

typedef pair<int,int> pii;
int nodecount,edgecount;

void dijkstra(int src,vector<vector<int>>g[1005],int dist[])
{
    priority_queue<pii,vector<pii>,greater<pii>>pq;
    pq.push({0,src});
    dist[src]=0;
    while(!pq.empty())
    {
        int u=pq.top().second;
        pq.pop();
        int sz=g[u].size();
        for(auto v: g[u])
        {
            int cost = dist[u] + v[1];
            if(dist[v[0]]>cost)
            {
                dist[v[0]]=cost;
                pq.push({cost,v[0]});
            }
        }
    }
}

int main()
{
    cin>>nodecount>>edgecount;
    int dist[nodecount];
    vector<vector<int>>g[1005];
    for(int i=1;i<=nodecount;i++)
    {
        dist[i]=INT_MAX/2;
    }
    for(int i=1; i<=edgecount;i++)
    {
        int u,v,weight;
        cin>>u>>v>>weight;
        g[u].push_back({v,weight});
        g[u].push_back({u,weight});
    }
    dijkstra(0,g,dist);
    for(int i=0;i<nodecount;i++)
        cout<<i<<" "<<dist[i]<<endl;
    return 0;
}