#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#include<queue>
#define N 2005
#define db double 
#define ll long long
#define ul unsigned long long
#define int long long
#define fo(i,l,r) for(int i=l;i<=r;i++)
#define rf(i,r,l) for(int i=r;i>=l;i--)
using namespace std;
int n,m,h[N],cnt,d[N],ans;const int inf=1e18;bool b[N];
struct node{int u,w;bool operator<(node y)const{return w>y.w;}};
struct edg{int u,v,w,c;bool operator<(edg y){return w^y.w?w<y.w:c<y.c;}}ed[N];
struct edge{int v,w,n;}e[N<<1];
void ad(int u,int v,int w){e[++cnt]={v,w,h[u]};h[u]=cnt;}
int dijkstra(int s,int t){
	priority_queue<node>q;
	fo(i,1,n)d[i]=inf,b[i]=0;
	d[s]=0;q.push({s,0});
	while(q.size())
	{
		node u=q.top();q.pop();
		if(b[u.u])continue;
		b[u.u]=1;
		if(u.u==t)return u.w;
		for(int i=h[u.u];i;i=e[i].n)
		{
			int v=e[i].v,w=u.w+e[i].w;
			if(w>=d[v])continue;
			d[v]=w;q.push({v,w});
		}
	}
	return inf;
}
void swap(int &x,int &y){int t=x;x=y;y=t;}
int max(int x,int y){return x>y?x:y;}
int min(int x,int y){return x<y?x:y;}
int read(){
	int sum=0;bool f=0;char c=getchar();
	for(;c<48||c>57;c=getchar())if(c==45)f=1;
	for(;c>=48&&c<=57;c=getchar())sum=sum*10+(c&15);
	return f?-sum:sum;
}
signed main(){
	freopen("Roads.in","r",stdin);freopen("Roads.out","w",stdout);
	n=read();m=read();
	fo(i,1,m)ed[i]={read(),read(),read(),read()};
	sort(ed+1,ed+m+1);
	fo(i,1,m)
		if(ed[i].w<dijkstra(ed[i].u,ed[i].v))
			ad(ed[i].u,ed[i].v,ed[i].w),ad(ed[i].v,ed[i].u,ed[i].w),ans+=ed[i].c;
	printf("%lld",ans);
	return 0;
}