using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Practice
{
    class Program
    {
        private static int ReadAndParseInt()
        {
            return int.Parse(Console.ReadLine());
        }
        private static int[] ReadAndParseIntArr()
        {
            return Array.ConvertAll(Console.ReadLine().Split(' '), int.Parse);
        }
        private static long ReadAndParseLong()
        {
            return long.Parse(Console.ReadLine());
        }
        private static long[] ReadAndParseLongArr()
        {
            return Array.ConvertAll(Console.ReadLine().Split(' '), long.Parse);
        }
        static void Main(string[] args)
        {
            SolveA(args);
            //SolveB(args);
            //SolveC(args);
            //SolveD(args);


        }

        private struct Node
        {
            public int s;
            public int t;
            public int w;
        }
        private static void SolveA(string[] args)
        {
            int[] ve = ReadAndParseIntArr();
            int v = ve[0];
            int e = ve[1];

            List<Node> edges = new List<Practice.Program.Node>();
            for(int i = 0;i<e;++i)
            {
                int[] stw = ReadAndParseIntArr();
                edges.Add(new Node() { s = stw[0], t = stw[1], w = stw[2] });
            }

            List<Node> k = kruskal(v, e, edges);
            int sum = 0;
            foreach(Node node in k)
            {
                sum += node.w;
            }
            Console.WriteLine(sum);
        }

        private static List<Node> kruskal(int v, int e, List<Node> edges)
        {
            // Ｅの要素を整列
            edges.Sort((a, b) => a.w.CompareTo(b.w));
            var s = new UnionFind(v);
            var k = new List<Node>();

            for(int i=0;i<e;++i)
            {
                Node node = edges[i];
                if(s.find(node.s) != s.find(node.t))
                {
                    s.unite(node.s, node.t);
                    k.Add(node);
                }
            }
            return k;
        }
    }
    class UnionFind
    {
        int[] data;

        public UnionFind(int sz)
        {
            data = new int[sz];
            for (int i = 0; i < sz; i++)
            {
                data[i] = -1;
            }
        }

        public bool unite(int x, int y)
        {
            x = find(x);
            y = find(y);

            if (x == y) return false;

            if (data[x] > data[y])
            {
                int buf = x;
                x = y;
                y = buf;
            }

            data[x] += data[y];
            data[y] = x;

            return true;
        }

        public int find(int k)
        {
            if (data[k] < 0) return k;
            return data[k] = find(data[k]);
        }

        public int size(int k)
        {
            return -data[find(k)];
        }

        public bool is_same(int x, int y)
        {
            return find(x) == find(y);
        }
    }

    public class PriorityQueue<T> where T : IComparable
    {
        private IComparer<T> _comparer = null;
        private int _type = 0;

        private T[] _heap;
        private int _sz = 0;

        private int _count = 0;

        /// <summary>
        /// Priority Queue with custom comparer
        /// </summary>
        public PriorityQueue(int maxSize, IComparer<T> comparer)
        {
            _heap = new T[maxSize];
            _comparer = comparer;
        }

        /// <summary>
        /// Priority queue
        /// </summary>
        /// <param name="maxSize">max size</param>
        /// <param name="type">0: asc, 1:desc</param>
        public PriorityQueue(int maxSize, int type = 0)
        {
            _heap = new T[maxSize];
            _type = type;
        }

        private int Compare(T x, T y)
        {
            if (_comparer != null) return _comparer.Compare(x, y);
            return _type == 0 ? x.CompareTo(y) : y.CompareTo(x);
        }

        public void Push(T x)
        {
            _count++;

            //node number
            var i = _sz++;

            while (i > 0)
            {
                //parent node number
                var p = (i - 1) / 2;

                if (Compare(_heap[p], x) <= 0) break;

                _heap[i] = _heap[p];
                i = p;
            }

            _heap[i] = x;
        }

        public T Pop()
        {
            _count--;

            T ret = _heap[0];
            T x = _heap[--_sz];

            int i = 0;
            while (i * 2 + 1 < _sz)
            {
                //children
                int a = i * 2 + 1;
                int b = i * 2 + 2;

                if (b < _sz && Compare(_heap[b], _heap[a]) < 0) a = b;

                if (Compare(_heap[a], x) >= 0) break;

                _heap[i] = _heap[a];
                i = a;
            }

            _heap[i] = x;

            return ret;
        }

        public int Count()
        {
            return _count;
        }

        public T Peek()
        {
            return _heap[0];
        }

        public bool Contains(T x)
        {
            for (int i = 0; i < _sz; i++) if (x.Equals(_heap[i])) return true;
            return false;
        }

        public void Clear()
        {
            while (this.Count() > 0) this.Pop();
        }

        public IEnumerator<T> GetEnumerator()
        {
            var ret = new List<T>();

            while (this.Count() > 0)
            {
                ret.Add(this.Pop());
            }

            foreach (var r in ret)
            {
                this.Push(r);
                yield return r;
            }
        }

        public T[] ToArray()
        {
            T[] array = new T[_sz];
            int i = 0;

            foreach (var r in this)
            {
                array[i++] = r;
            }

            return array;
        }
    }
}



Measured memory_bytes: 24380