1 //# include <bits/stdc++.h>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <vector>
  5 #include <queue>
  6 using namespace std;
  7 # define eps 1e-8
  8 # define INF 0x3f3f3f3f
  9 # define pi  acos(-1.0)
 10 # define MXN  1005
 11 # define MXM  20050
 12 
 13 struct Edge{
 14     int from, to, flow, cost, cap;
 15 }edges[MXM*2];            //有向边数*2
 16 
 17 struct MCMF{
 18     int n, m, idx;    //点，边，边数
 19     int flow, cost;
 20     vector<int> G[MXN];     //记录边
 21     int inq[MXN];           //BFS用
 22     int dis[MXN];           //层次
 23     int pre[MXN];           //上一条弧
 24     int adf[MXN];           //增量
 25 
 26     void Init(){
 27         idx=0;
 28         for (int i=0;i<=n+1;i++) G[i].clear();    //有附加点时要注意
 29     }
 30 
 31     void Addedge(int u,int v,int cost,int cap){
 32         edges[idx++] = (Edge){u,v,0,cost,cap};
 33         edges[idx++] = (Edge){v,u,0,-cost,0};
 34         G[u].push_back(idx-2);
 35         G[v].push_back(idx-1);
 36     }
 37 
 38     int Bellman(int s, int t)
 39     {
 40         memset(dis,0x3f,sizeof(dis));   //有附加点时要注意
 41         memset(inq,0,sizeof(inq));
 42         dis[s]=0, inq[s]=1, adf[s]=INF;
 43         queue<int> Q;
 44         Q.push(s);
 45         while (!Q.empty())
 46         {
 47             int u = Q.front(); Q.pop();
 48             inq[u]=0;
 49             for (int i=0;i<(int)G[u].size();i++)
 50             {
 51                 Edge &e = edges[G[u][i]];
 52                 if (dis[e.to] > dis[u] + e.cost && e.cap > e.flow)
 53                 {
 54                     dis[e.to] = dis[u] + e.cost;
 55                     adf[e.to] = min(adf[u], e.cap-e.flow);
 56                     pre[e.to] = G[u][i];
 57                     if (!inq[e.to])
 58                     {
 59                         Q.push(e.to);
 60                         inq[e.to]=1;
 61                     }
 62                 }
 63             }
 64         }
 65         if (dis[t]==INF) return false;
 66 
 67         flow+=adf[t];
 68         cost+=adf[t]*dis[t];
 69         int x=t;
 70         while(x!=s)
 71         {
 72             edges[pre[x]].flow+=adf[t];
 73             edges[pre[x]^1].flow-=adf[t];
 74             x=edges[pre[x]].from;
 75         }
 76         return true;
 77     }
 78 
 79     int MinCost(int s,int t)
 80     {
 81         flow = 0, cost = 0;
 82         while(Bellman(s, t));
 83         return cost;
 84     }
 85 }F;
 86 
 87 int main()
 88 {
 89     scanf("%d%d",&F.n,&F.m);
 90     F.Init();
 91     for (int i=1;i<=F.m;i++)
 92     {
 93         int u,v,cost;
 94         scanf("%d%d%d",&u,&v,&cost);
 95         F.Addedge(u,v,cost,1);
 96         F.Addedge(v,u,cost,1);
 97     }
 98     F.Addedge(0, 1, 0, 2);
 99     F.Addedge(F.n, F.n+1, 0, 2);
100     printf("%d\n",F.MinCost(0,F.n+1));
101     return 0;
102 }