#include<bits/stdc++.h>
const int N=1e6+50;
int n, m, min[N],out[N],f[N],siz[N],ans;

struct edge
{
	int u, v, w;
} e[N];

inline int find(int x)
{
	while (x!=f[x])
		x=f[x]=f[f[x]];
	return x;
}

inline void merge(int x,int y)
{
	if (siz[x]>siz[y]) std::swap(x,y);
	f[x]=y;
}

int main()
{
	scanf ("%d%d", &n, &m);
	for (int i=1; i<=n; ++i)
	{
		f[i]=i,siz[i]=1;
	}
	for (int i=1; i<=m; ++i)
	{
		scanf ("%d%d%d", &e[i].u,&e[i].v,&e[i].w);
	}
	int components=n;
	while (components>1)
	{
		memset (min,0x3f,sizeof (min));
		for (int i=1; i<=m; ++i)
		{
			int u=find(e[i].u),v=find(e[i].v),w=e[i].w;
			if (u!=v)
			{
				if (w<min[u]) min[u]=w,out[u]=v;
				if (w<min[v]) min[v]=w,out[v]=u;
			}
		}
		for (int i=1; i<=n; ++i)
		{
			int x=find(i) ;
			if (out[x])
			{
				int y=find(out[x]);
				if (x!=y)
				{
					merge(x,y);
					--components;
					ans+=min[x];
				}
			}
		}
	}
	printf("%d",ans);
	return 0;
}