#include <bits/stdc++.h>
using namespace std;
const int N=5100;
int n,m,ans,g[N][N],minn[N];
bool vis[N];
int main()
{
	std::ios::sync_with_stdio(0);
	cin>>n>>m;
	memset(minn,0x3f3f3f,sizeof(minn));
	memset(vis,0,sizeof(vis));
	memset(g,0x3f3f3f,sizeof(g));
	for(int i=1;i<=m;i++){int u,v,w;cin>>u>>v>>w;g[u][v]=w;g[v][u]=w;}
	int cat=0;
	for(int i=1;i<=n;i++)
	{
		cat=0;
		for(int j=1;j<=n;j++)
		{
			if(!vis[j]&&(minn[cat]>minn[j]))
			{
				cat=j;
			}
		}
		vis[cat]=1;
		for(int j=1;j<=n;j++)
		{
			if(!vis[j]&&(minn[j]>g[cat][j]))
			{
				minn[j]=g[cat][j];
			}
		}
	}
	for(int i=1;i<=n;i++)
	{
		ans+=minn[i];
	}
	cout<<ans;
	return 0;
}