using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using static System.Math;
using System.Text.RegularExpressions;

namespace CsharpSpiral {
    partial class Program {
        static void Main(string[] args) {
            var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);
            new Program().Solve(new ConsoleInput(Console.In, ' '));
            Console.Out.Flush();
        }
        public void Solve(ConsoleInput cin) {
            var n = cin.ReadInt;
            var G = new Graph(n);
            for(int i = 0; i < n; i++) {
                var u = cin.ReadInt;
                var k = cin.ReadInt;
                for(int j = 0; j < k; j++) {
                    var v = cin.ReadInt;
                    var c = cin.ReadInt;
                    G.AddEdge(u, v, c);
                }
            }
            var D = G.Dijkstra(0);
            Console.WriteLine(D.Select((x, i) => $"{i} {x}").ToArray().Join("\n"));
        }
    }

    static class ExtendClass {
        public static string Join<T>(this T[] X, string separator = " ") => string.Join(separator, X);
        public static S[] Clone<S>(this S[] src) where S : struct {
            var res = new S[src.Length];
            Array.Copy(src, res, src.Length);
            return res;
        }
    }

    class ConsoleInput {
        private readonly TextReader _stream;
        private readonly char _separator = ' ';
        private readonly Queue<string> inputStream;
        public ConsoleInput(TextReader stream, char separator = ' ') {
            this._separator = separator;
            this._stream = stream;
            inputStream = new Queue<string>();
        }
        public string Read {
            get {
                if(inputStream.Count != 0) return inputStream.Dequeue();
                string[] tmp = _stream.ReadLine().Split(_separator);
                for(int i = 0; i < tmp.Length; ++i)
                    inputStream.Enqueue(tmp[i]);
                return inputStream.Dequeue();
            }
        }
        public string ReadLine { get { return _stream.ReadLine(); } }
        public int ReadInt { get { return int.Parse(Read); } }
        public long ReadLong { get { return long.Parse(Read); } }
        public double ReadDouble { get { return double.Parse(Read); } }
        public string[] ReadStrArray(long N) {
            var ret = new string[N];
            for(long i = 0; i < N; ++i)
                ret[i] = Read;
            return ret;
        }
        public int[] ReadIntArray(long N) { var ret = new int[N]; for(long i = 0; i < N; ++i) ret[i] = ReadInt; return ret; }
        public long[] ReadLongArray(long N) { var ret = new long[N]; for(long i = 0; i < N; ++i) ret[i] = ReadLong; return ret; }
        public double[] ReadDoubleArray(long N) { var ret = new double[N]; for(long i = 0; i < N; ++i) ret[i] = ReadDouble; return ret; }
    }
	class Edge<V> where V : IComparable<V> {
		public int In { get; set; }
		public int Out { get; set; }
		public V cost { get; set; }
		public Edge<V> parent { get; set; }
	}
	class Node<V>: IComparable<Node<V>> where V : IComparable<V> {
		public V Value { get; set; }
		public int index { get; set; }
		public int CompareTo(Node<V> y) => Value.CompareTo(y.Value);
	}
	class Graph: Graph<long> {
		public Graph(int count) : base(count) { }
		public long[] Dijkstra(int start) {
			var PQ = new ImmutablePriorityQueue<Node<long>>(false);
			const long large = 0x3FFFFFFFFFFFFFFF;
			var Nodes = new Node<long>[N];
			var picked = new bool[N];
			var parentIndex = Enumerable.Repeat(-1, N).ToArray();
			var O = Outs;
			for(int i = 0; i < N; i++) {
				Nodes[i] = new Node<long> {
					index = i,
					Value = i == start ? 0 : large
				};
				PQ.Push(Nodes[i]);
			}
			while(PQ.Any()) {
				var nv = PQ.Pop();
				var v = nv.index;
				picked[v] = true;
				foreach(var e in O[v]) {
					var w = e.Out;
					if(picked[w]) continue;
					var c = e.cost;
					if(Nodes[v].Value + c < Nodes[w].Value) {
						Nodes[w].Value = Nodes[v].Value + c;
						PQ.Update(Nodes[w]);
						parentIndex[w] = v;
					}
				}
			}
			return Nodes.Select(n => n.Value).ToArray();
		}
	}
	class Graph<V> where V : IComparable<V> {
		public int N { get; }
		public Graph(int count) {
			N = count;
			Edges = new List<Edge<V>>();
		}
		public List<Edge<V>> Edges { get; }
		public void AddEdge(int In, int Out, V Value) {
			var e = new Edge<V> { In = In, Out = Out, cost = Value };
			Edges.Add(e);
		}
		protected List<Edge<V>>[] Outs {
			get {
				var Res = new List<Edge<V>>[N];
				for(int i = 0; i < N; i++)
					Res[i] = new List<Edge<V>>();
				foreach(var e in Edges)
					Res[e.In].Add(e);
				return Res;
			}
		}
		protected List<Edge<V>>[] Ins {
			get {
				var Res = new List<Edge<V>>[N];
				for(int i = 0; i < N; i++)
					Res[i] = new List<Edge<V>>();
				foreach(var e in Edges)
					Res[e.Out].Add(e);
				return Res;
			}
		}
		
	}

	class PriorityQueue<T> where T : IComparable<T> {
		protected readonly List<T> body = new List<T>();
		protected Comparer<T> comparer { get; set; }
		public PriorityQueue(bool maxTop = true) {
			comparer
			= maxTop ? Comparer<T>.Create((T i, T j) => i.CompareTo(j))
			: Comparer<T>.Create((T i, T j) => j.CompareTo(i));
		}
		public PriorityQueue(Comparer<T> mComparer) { comparer = mComparer; }
		//suppose Me>Her if isRootMaximum
		protected int Compare(T Me, T Her) => comparer.Compare(Me, Her);
		protected int Compare(int x, int y) => Compare(body[x], body[y]);
		protected virtual void Swap(int x, int y) { T tmp = body[x]; body[x] = body[y]; body[y] = tmp; }
		public virtual void Push(T elem) {
			body.Add(elem);
			//the parent of n-th element is the ((n+1)>>1)-1-th
			UpHeap(lastIndex);
		}
		public void Push(IEnumerable<T> seq) {
			foreach(var item in seq) {
				Push(item);
			}
		}
		protected int UpHeap(int j) {
			while(j > 0) {
				int parent = ((j + 1) >> 1) - 1;
				if(Compare(parent, j) < 0) {
					Swap(parent, j);
				} else break;
				j = parent;
			}
			return j;
		}
		public virtual T Pop() {
			T top = body[0];
			Swap(0, lastIndex);
			body.RemoveAt(lastIndex);
			DownHeap(0);
			return top;
		}
		protected int DownHeap(int j) {
			while(j < length) {
				var leftChild = ((j + 1) << 1) - 1;
				if(leftChild >= length) break;
				var toSwap = leftChild;
				var rightChild = leftChild + 1;
				if(rightChild < length && Compare(leftChild, rightChild) < 0)
					toSwap = rightChild;
				if(Compare(j, toSwap) < 0) {
					Swap(toSwap, j);
				} else break;
				j = toSwap;
			}
			return j;
		}
		public T Top { get { return body[0]; } }
		public int length { get { return body.Count(); } }
		protected int lastIndex { get { return body.Count() - 1; } }
		public bool Any() => body.Any();
		public string Emit() { return body.ToArray().Join(","); }
	}
	class ImmutablePriorityQueue<T>: PriorityQueue<T> where T : IComparable<T> {
		public Dictionary<T, int> map { get; private set; } = new Dictionary<T, int>();
		public ImmutablePriorityQueue(bool maxTop) : base(maxTop) { }
		public ImmutablePriorityQueue(Comparer<T> mComparer) : base(mComparer) { }
		protected override void Swap(int x, int y) {
			map[body[x]] = y;
			map[body[y]] = x;
			base.Swap(x, y);
		}
		public override void Push(T elem) {
			map.Add(elem, length);
			base.Push(elem);
		}
		public override T Pop() {
			var V = base.Pop();
			map.Remove(V);
			return V;
		}
		public void Remove(T X) {
			var x = map[X];
			map.Remove(X);
			Swap(x, lastIndex);
			body.RemoveAt(lastIndex);
			var b = DownHeap(x);
			if(b == x) UpHeap(x);
		}
		public void Update(T X) {
			var x = map[X];
			var b = DownHeap(x);
			if(b == x) UpHeap(x);
		}
		public bool hasKey(T X)  {int j; return map.TryGetValue(X, out j); }
	}
}



Measured memory_bytes: 19288