#include<cstdio>
#include<queue>
#include<vector>
#include<iostream>
using namespace std;
int d[10005], visited[10005];
vector<pair<int, int>> G[10005];
int n, INFTY = (1<<30);
priority_queue<pair<int, int>> Q;
void dijkstra()
{
  for(int i=0; i<n; i++)
  {
    d[i] = INFTY; visited[i] = 0;
  }
  d[0] = 0;
  Q.push(make_pair(0, 0));
  while(!Q.empty())
  {
    int c = Q.top().first;
    int v = Q.top().second;
    Q.pop();
    //if(d[v] < -c) break;
    visited[v] = 1;
    for(int i=0; i<G[v].size(); i++)
    {
      pair<int, int> p = G[v][i];
      int u = p.second, cost = p.first;
      if(visited[u]==0 && d[u] > cost + d[v])
      {
        d[u] = cost + d[v];
        Q.push(make_pair(-d[u], u));
      }
    }
  }
  for(int i=0; i<n; i++)
  {
    printf("%d %d\n", i, d[i]);
  }
}
int main()
{
  scanf("%d", &n);
  int u, v, c, k;
  for(int i=0; i<n; i++)
  {
    scanf("%d%d", &u, &k);
    for(int j=0; j<k; j++)
    {
      scanf("%d%d", &v, &c);
      G[u].push_back(make_pair(c, v));
    }
  }
  dijkstra();
  return 0;
}

