#include<bits/stdc++.h>
#define s(x) scanf("%d",&x);
#define p(x) printf("%d",x);
#define ps(x) printf(x);
#define f(x,y,z) for(int x=y;x<=z;x++)
#define r return 0;
using namespace std;
int n,m,dis[5010],a[5010][5010],x,y,z,minn,k,b[5010],ans;
int main()
{
	cin>>n>>m;
	memset(a,0x3f,sizeof(a));
	f(i,1,m)
	{
		s(x)s(y)s(z)
		a[x][y]=z;
	}
	memset(dis,0x3f,sizeof(dis));
	dis[1]=0;
	f(i,1,n)
	{
		minn=0x3f3f3f3f;k=0;
		f(j,1,n)
		{
			if(b[j]==0&&dis[j]<minn)
			{
				minn=dis[j];
				k=j;
			}
		}
		if(k==0)
		{
			ps("orz");
			r
		}
		b[k]=1;
		ans+=dis[k];
		f(j,1,n)
		{
			if(b[j]==0&&a[k][j]<dis[j]) dis[j]=a[k][j];
		}
	}
	p(ans);
	r
} 

本人码风较差，请大家多多谅解