#include<cstdio>
#include<queue>
#include<cstring>
#define N 2000005
#define inf 0x7fffffff
#define LL long longusing namespace std;
int tot,n,m,head1[N],d[N],vis[N],head2[N],tpt;
LL ans;
struct node{int to,next,dis;
};
node e1[N],e2[N];void add(int u,int v,int w,int tp){if(tp==1){e1[++tot].to=v;e1[tot].next=head1[u];head1[u]=tot;e1[tot].dis=w;}else {e2[++tpt].to=v;e2[tpt].next=head2[u];head2[u]=tpt;e2[tpt].dis=w;}
}inline void spfa(int st,int tp){for(int i=1;i<=n;i++) d[i]=inf;memset(vis,0,sizeof(vis));d[st]=0;vis[st]=1;queue<int>q;q.push(st);if(tp==1)while(!q.empty()){int x=q.front();q.pop();vis[x]=0;for(int i=head1[x];i;i=e1[i].next){int to=e1[i].to,w=e1[i].dis;if(d[x]+w<d[to]){d[to]=d[x]+w;if(!vis[to]){q.push(to);vis[to]=1;}}} }elsewhile(!q.empty()){int x=q.front();q.pop();vis[x]=0;for(int i=head2[x];i;i=e2[i].next){int to=e2[i].to,w=e2[i].dis;if(d[x]+w<d[to]){d[to]=d[x]+w;if(!vis[to]){q.push(to);vis[to]=1;}}} }
}
int main()
{scanf("%d%d",&n,&m);for(int i=1;i<=m;i++){int u,v,w;scanf("%d%d%d",&u,&v,&w);add(u,v,w,1);add(v,u,w,2);}spfa(1,1);for(int i=1;i<=n;i++){ans+=d[i];}spfa(1,2);for(int i=1;i<=n;++i){ans+=d[i];}printf("%lld",ans);return 0;
} 

// luogu-judger-enable-o2
#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <vector>
#include <stack>
#include <queue>
#define LL long long
using namespace std;
#define LL long long
LL n,m,s,ans;
typedef pair<LL,int> pii;
struct ahah{int nxt,to,dis;
}edge1[1000010],edge2[1000006];
int head1[1000010],tot1,head2[1000006],tot2;
void add(int x,int y,int z,int flag)
{if(flag==1)edge1[++tot1].nxt=head1[x],edge1[tot1].to=y,edge1[tot1].dis=z,head1[x]=tot1;else edge2[++tot2].nxt=head2[x],edge2[tot2].to=y,edge2[tot2].dis=z,head2[x]=tot2;
}
priority_queue <pii,vector<pii>,greater<pii> >Q;
bool vis[1000010];
LL d[1000010];
void dijkstra1(int s)
{for(int i=1;i<=n;i++)d[i]=1e15;Q.push(make_pair(0,s));d[s]=0;while(!Q.empty()){while(!Q.empty()&&vis[Q.top().second])Q.pop();if(Q.empty())return ;int temp=Q.top().second;d[temp]=Q.top().first;vis[temp]=1;Q.pop();for(int i=head1[temp];i;i=edge1[i].nxt){if(!vis[edge1[i].to])Q.push(make_pair(d[temp]+edge1[i].dis,edge1[i].to));}}return ;
}
void dijkstra2(int s)
{for(int i=1;i<=n;i++)d[i]=1e15;Q.push(make_pair(0,s));d[s]=0;while(!Q.empty()){while(!Q.empty()&&vis[Q.top().second])Q.pop();if(Q.empty())return ;int temp=Q.top().second;d[temp]=Q.top().first;vis[temp]=1;Q.pop();for(int i=head2[temp];i;i=edge2[i].nxt){if(!vis[edge2[i].to])Q.push(make_pair(d[temp]+edge2[i].dis,edge2[i].to));}}return ;
}
main()
{int x,y,z;scanf("%lld%lld",&n,&m);for(int i=1;i<=m;i++){scanf("%d%d%d",&x,&y,&z);add(x,y,z,1);add(y,x,z,2);}dijkstra1(1);for(int i=2;i<=n;i++)ans+=d[i];memset(vis,0,sizeof(vis));dijkstra2(1);for(int i=2;i<=n;i++)ans+=d[i];printf("%lld",ans);
}