#include<cstdio> #include<vector> #include<queue> using namespace std; struct edge { int to,val; }; priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > >q; vector<edge>e[2505]; int dis[2505]; int vis[2505]; int main() { int n,m; scanf("%d%d",&n,&m); for(int i=1;i<=m;i++) { int x,y,z; scanf("%d%d%d",&x,&y,&z); edge tmp; tmp.to=y; tmp.val=z; e[x].push_back(tmp); tmp.to=x; tmp.val=z; e[y].push_back(tmp); } for(int i=1;i<=n;i++) { dis[i]=2147483647; } dis[1]=0; q.push(make_pair(0,1)); while(!q.empty()) { int x=q.top().second; q.pop(); if(vis[x]==1) continue; vis[x]=1; for(int i=0;i<e[x].size();i++) { int y=e[x][i].to; if(dis[x]+e[x][i].val<dis[y]) { dis[y]=dis[x]+e[x][i].val; q.push(make_pair(dis[y],y)); } } } printf("%d\n",dis[n]); return 0; }