#include<bits/stdc++.h>
using namespace std;
static const int INF=1000000;

int n;
vector<pair<int,int> > nex[10000];

void dijkstra(){ 
  priority_queue<pair<int,int> >PQ;
  int d[10000];
  int color[10000];  
  for(int i=0;i<n;i++){
    d[i]=INF;
    color[i]=0;
  }
  
  color[0]=1;
  d[0]=0;
  PQ.push(make_pair(0, 0));
  
  while( !PQ.empty() ){
    pair<int,int> f = PQ.top();PQ.pop();
    int u =f.second;
    color[u]=2;
    if(d[u] < f.first *(-1)) continue;
    
    for(int j=0;j<nex[u].size();j++){
      int v=nex[u][j].first;
      if(color[v] == 2) continue;
      if(d[v]>d[u]+nex[u][j].second){
        d[v]=d[u]+nex[u][j].second;
        PQ.push(make_pair(d[v]*(-1),v));
        color[v]=1;
      }
    }
  }
  for(int i=0;i<n;i++){
    cout<<i<<" "<<(d[i] == INF ?:d[i])<<endl;
  }
}


int main(){
  cin>>n;
  int u,k,v,c;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v>>c;
      nex[u].push_back(make_pair(v,c));
    }
  }
  
  dijkstra();
  return 0;
}

      
  
