#include<bits/stdc++.h>
using namespace std;

long long ans=0;
int n,m,cnt,x[100005],y[100005],z[100005],head[100005],dis[100005],vis[100005];

priority_queue <pair <long long,int> >Q;

struct newt
{
    int to;
	int next;
	int val;
}
edge[1000005];

void addedge(int u,int v,int w)
{
    edge[++cnt].next=head[u];
	head[u]=cnt;
    edge[cnt].to=v;
	edge[cnt].val=w;
}

void dijstla(int s)
{
	memset(dis,0x3f,sizeof(dis));
	dis[s]=0;
	Q.push (make_pair(0,s));
	while (!Q.empty())
	{
		int now=Q.top().second;
		Q.pop();
		if (vis[now]) continue;
		vis[now]=1;
		for (int i=head[now];i;i=edge[i].next)
		{
			int v=edge[i].to;
			if (dis[v]>edge[i].val+dis[now])
			{
				dis[v]=edge[i].val+dis[now];
				Q.push (make_pair(dis[v],v));
			}
		}
	}
	for (int i=1;i<=m;i++)
	{
		ans+=dis[i];
	}
}

int main()
{
	cin>>m>>n;
	for (int i=1;i<=n;i++)
	{
		cin>>x[i]>>y[i]>>z[i];
		addedge(x[i],y[i],z[i]);
	}
	dijstla(1);
	memset(vis,0,sizeof(vis));
	memset(head,0,sizeof(head));
	memset(edge,0,sizeof(edge));
	for (int i=1;i<=n;i++)
	{
		addedge(y[i],x[i],z[i]);
	}
	dijstla(1);
	cout<<ans;
	return 0;
}

样例过了，为什么全wa，QWQ