using System;
using System.Collections.Generic;
using System.Linq;
using static System.Console;
using static System.Convert;
using static System.Math;
//using static System.Globalization.CultureInfo;

class Program
{ 
    static void Main(string[] args)
    {
        var num = Input.num;
        var ps = Enumerable.Range(0, num).Select(v => new P(v)).ToArray();
        for(var i = 0; i < num; i++)
        {
            var inp = Input.ar;
            for(var j = 1; j <= inp[1]; j++)
            {
                ps[i].adj.Add(inp[2*j]);
                ps[i].dist[inp[2 * j]] = inp[2 * j + 1];
            }
        }
        var pq = new PriorityQueue<P>(false, new P(-1, long.MaxValue));
        ps[0].Weight = 0;
        pq.Enqueue(ps[0]);
        while (!pq.isEmpty)
        {
            var p = pq.Dequeue();
            foreach (var ad in p.adj)
                if (ps[ad].Weight > p.Weight+p.dist[ad])
                {
                    ps[ad].Weight = p.Weight+p.dist[ad];
                    pq.Enqueue(ps[ad]);
                }
        }
        WriteLine(string.Join("\n",ps.Select(p=>$"{p.index} {p.Weight}")));
    }
}

public class Input
{
    public static string read => ReadLine();
    public  static int[] ar => Array.ConvertAll(read.Split(' '), int.Parse);
    public  static int num => ToInt32(read);
    public static long[] arL => Array.ConvertAll(read.Split(' '), long.Parse);
    public  static long numL => ToInt64(read);
    public static int[][] twodim(int num)
        => Enumerable.Repeat(0, num).Select(v => ar).ToArray();
    public static long[][] twodimL(int num)
        => Enumerable.Repeat(0, num).Select(v => arL).ToArray();
    public const double eps = 1e-11;
    public  const string Alfa = "abcdefghijklmnopqrstuvwxyz";
    public  const int MOD = 1000000007;
}

public class P : IComparable<P>
{
    public int index;
    public List<int> adj;
    public Dictionary<int, int> dist;
    public long Weight;
    public P(int index):this(index,(long)1e18)
    {
    }
    public P(int index,long Weight)
    {
        this.index = index;
        adj = new List<int>();
        dist = new Dictionary<int, int>();
        this.Weight = Weight; 
    }
    public static P[] Make(int num, int edge, bool isNotDirected = true, bool isWeighted = true)
    {
        var ps = Enumerable.Range(0, num).Select(v => new P(v)).ToArray();
        for (var i = 0; i < edge; i++)
        {
            var inp = Input.ar;
            //inp[0]--;
            //inp[1]--;
            for (var j = 0; j <= ToInt32(isNotDirected); j++)
            {
                ps[inp[j]].adj.Add(inp[1 - j]);
                if(isWeighted)
                ps[inp[j]].dist[inp[1 - j]] = inp[2];
            }
        }
        return ps;
    }
    public override string ToString()
        => $"{index + 1} {Weight}";
    public override int GetHashCode()
        => index.GetHashCode();
    public int CompareTo(P p)
        => Weight.CompareTo(p.Weight);
}

public class PriorityQueue<T> where T : IComparable<T>
{
    private readonly List<T> items;
    private T MinValue { get; }//一番優先度が低い値

    public bool IsMax { get; }
    public int Size { get { return items.Count; } }
    public bool isEmpty { get { return items.Count == 0; } }
    
    public PriorityQueue(T minValue) : this(true, minValue)
    {

    }

    public PriorityQueue(bool IsMax, T MinValue)
    {
        this.items = new List<T>();
        this.IsMax = IsMax;
        this.MinValue = MinValue;
    }

    private int Parent(int num)
    {
        return (int)Math.Ceiling((double)num / 2) - 1;
    }
    private int Left(int num)
    { 
        return 2 * num + 1;
    }
    private int Right(int num)
    { 
        return 2 * (num + 1);
    }

    private void MaxHeapify(int num)
    {
        var left = Left(num);
        var right = Right(num);
        var largest = 0;
        if (Size >= left + 1 && items[left].CompareTo(items[num]) == 1)
            largest = left;
        else largest = num;
        if (Size >= right + 1 && items[right].CompareTo(items[largest]) == 1)
            largest = right;
        if (largest != num)
        {
            var value = items[largest];
            items[largest] = items[num];
            items[num] = value;
            MaxHeapify(largest);
        }
    }

    private void MinHeapify(int num)
    {
        var left = Left(num);
        var right = Right(num);
        var smallest = 0;
        if (Size >= left + 1 && items[num].CompareTo(items[left]) == 1) smallest = left;
        else smallest = num;
        if (Size >= right + 1 && items[smallest].CompareTo(items[right]) == 1) smallest = right;
        if (smallest != num)
        {
            var value = items[smallest];
            items[smallest] = items[num];
            items[num] = value;
            MinHeapify(smallest);
        }
    }

    private void BuildHeap()
    {
        for (var i = (int)Math.Ceiling((double)Size / 2) - 1; i >= 0; i--)
        {
            if (IsMax) MaxHeapify(i);
            else MinHeapify(i);
        }
    }
    

    private bool ChangeKey(int index, T reValue)
    {
        if (IsMax && items[index].CompareTo(reValue) == 1)
            return false;
        if (!IsMax && items[index].CompareTo(reValue) == -1)
            return false;
        items[index] = reValue;
        if (IsMax)
        {
            while (index > 0 && items[Parent(index)].CompareTo(items[index]) == -1)
            {
                var value = items[Parent(index)];
                items[Parent(index)] = items[index];
                items[index] = value;
                index = Parent(index);
            }
        }
        else
        {
            while (index > 0 && items[Parent(index)].CompareTo(items[index]) == 1)
            {
                var value = items[Parent(index)];
                items[Parent(index)] = items[index];
                items[index] = value;
                index = Parent(index);
            }
        }
        return true;
    }

    public T Peek { get { return items[0]; } }

    public T Dequeue()
    {
        if (Size <= 0) return default(T);
        var value = items[0];
        items[0] = items[Size - 1];
        items.RemoveAt(Size - 1);
        if (IsMax) MaxHeapify(0);
        else MinHeapify(0);
        return value;
    }

    public bool Enqueue(T key)
    {
        items.Add(MinValue);
        return ChangeKey(Size-1, key);
    }

    private bool Delete(int index)
    {
        if (index >= Size)
            return false;
        var value = items[index];
        items[index] = items[Size - 1];
        items[Size - 1] = value;
        items.RemoveAt(Size - 1);
        if (IsMax) MaxHeapify(0);
        else MinHeapify(0);
        return true;
    }
}



Measured memory_bytes: 56940