#include <iostream>
#include <algorithm>

typedef long long ll;
typedef double lf;

struct IO
{
    #define MAXSIZE (1 << 20)
    #define isdigit(x) (x >= '0' && x <= '9')
    char buf[MAXSIZE], *p1, *p2;
    char pbuf[MAXSIZE], *pp;
    #if DEBUG
    #else
    IO() : p1(buf), p2(buf), pp(pbuf) {}
    ~IO() {fwrite(pbuf, 1, pp - pbuf, stdout);}
    #endif
    #define gc() (p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, MAXSIZE, stdin), p1 == p2) ? ' ' : *p1++)
    #define blank(x) (x == ' ' || x == '\n' || x == '\r' || x == '\t')

    template <typename T>
    void Read(T &x)
    {
        #if DEBUG
        std::cin >> x;
        #else
        bool sign = 0; char ch = gc(); x = 0;
        for (; !isdigit(ch); ch = gc())
            if (ch == '-') sign = 1;
        for (; isdigit(ch); ch = gc()) x = x * 10 + (ch ^ 48);
        if (sign) x = -x;
        #endif
    }
    void Read(char *s)
    {
        #if DEBUG
        std::cin >> s;
        #else
        char ch = gc();
        for (; blank(ch); ch = gc());
        for (; !blank(ch); ch = gc()) *s++ = ch;
        *s = 0;
        #endif
    }
    void Read(char &c) {for (c = gc(); blank(c); c = gc());}

    void Push(const char &c)
    {
        #if DEBUG
        putchar(c);
        #else
        if (pp - pbuf == MAXSIZE) fwrite(pbuf, 1, MAXSIZE, stdout), pp = pbuf;
        *pp++ = c;
        #endif
    }
    template <typename T>
    void Write(T x)
    {
        if (x < 0) x = -x, Push('-');
        static T sta[35];
        int top = 0;
        do sta[top++] = x % 10, x /= 10; while (x);
        while (top) Push(sta[--top] ^ 48);
    }
    template <typename T>
    void Write(T x, char lst) {Write(x), Push(lst);}
} IO;
#define Read(x) IO.Read(x)
#define Write(x, y) IO.Write(x, y)
#define Put(x) IO.Push(x)

using namespace std;

const int MAXN = 2e5 + 10, MAXM = 5e5 + 10;

int n, m;

struct Edge
{
    int u, v, w;
    bool operator < (const Edge u) const {return w < u.w;}
}e[MAXM];

int fa[MAXN];
inline int Find(int k) {return k == fa[k] ? k : fa[k] = Find(fa[k]);}

int main()
{
    ios::sync_with_stdio(0), cin.tie(0);
    Read(n), Read(m);
    for (int i = 1; i <= m; i++) Read(e[i].u), Read(e[i].v), Read(e[i].w);
    sort(e + 1, e + m + 1);
    for (int i = 1; i <= n; i++) fa[i] = i;
    ll ans = 0;
    for (int i = 1; i <= m; i++)
    {
        int u = Find(e[i].u), v = Find(e[i].v);
        if (u == v) continue;
        fa[u] = v, ans += e[i].w;
    }
    cout << ans << '\n';
}