#include <iostream>
#include <cmath>
#include <vector>
#include <iterator>
#include <set>
using namespace std;

void mergesort(long *weight, long *x, long *y, long l, long r)
{
    long j=l, k, i;
    long m[r], cpyx[r], cpyy[r];
    long middle;
    middle = (r + l) / 2;
    k = middle + 1;
    for (i = l; i <= r; i++)
    {
        if (((k > r) || (weight[j] < weight[k])) && (j <= middle))
        {
            m[i] = weight[j];
            cpyx[i] = x[j];
            cpyy[i] = y[j];
            j ++;
        }
        else
        {
            m[i] = weight[k];
            cpyx[i] = x[k];
            cpyy[i] = y[k];
            k ++;
        }
    }
    for (i = l; i <= r; i++)
    {
        weight[i] = m[i];
        x[i] = cpyx[i];
        y[i] = cpyy[i];
	}
};

void merge(long *weight, long *x, long* y, long l, long r)
{
    if (l < r)
    {
        merge(weight, x, y, l, (l + r) / 2);
        merge(weight, x, y, (l + r) / 2 + 1, r);
        mergesort(weight, x, y, l, r);
    }
};

int main()
{
	long n, m, i;
//    freopen("spantree3.in", "r", stdin);
//    freopen("spantree3.out", "w", stdout);
    cin >> n >> m;
    long x[m], y[m], weight[m];
    set <long> comp[n];
    vector<long> flags;
    for (i = 1; i <= m; i++)
        cin >> x[i] >> y[i] >> weight[i];
    flags.resize(n);
	for (i = 1; i <= n; i++)
		flags[i] = 0;
    merge(weight, x, y, 1, m);
	long long sum = 0;
	long k = 1;
	for (i = 1; i <= m; i++)
	{
		if (((flags[x[i]] == 0) && (flags[y[i]] == 0)) && (x[i] != y[i]))
		{
			comp[k].insert(x[i]);
			comp[k].insert(y[i]);
			flags[x[i]] = k;
			flags[y[i]] = k;
			k++;
			sum += weight[i];
		}
		else
		{
			if ((flags[x[i]] != 0) && (flags[y[i]] == 0))
			{
				flags[y[i]] = flags[x[i]];
				comp[flags[x[i]]].insert(y[i]);
				sum += weight[i];
			}
			else
			{
				if ((flags[y[i]] != 0) && (flags[x[i]] == 0))
				{
					flags[x[i]] = flags[y[i]];
					comp[flags[y[i]]].insert(x[i]);
					sum += weight[i];
				}
				else
					if ((flags[x[i]] != 0) && (flags[y[i]] != 0) && (flags[x[i]] != flags[y[i]]))
					{
						int cop = flags[y[i]];
						for (auto z:comp[flags[y[i]]])
						{
							comp[flags[x[i]]].insert(z);
							flags[z] = flags[x[i]];
						}
						sum += weight[i];
					}
			}
		}
	}
	cout << sum;
	return 0;
}
/*
4 4
1 2 1
2 3 2
3 4 5
4 1 4
*/
/*
4 3
1 3 1
1 2 2
2 4 1
*/