#include<algorithm> #include<iostream> #include<cstdio> using namespace std; inline int read(){ int x=0,f=1;char ch=getchar(); while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();} while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();} return x*f; } struct edge{ int x,y,z; }e[20001]; int n,m,cnt=1,ans,tot,fa[1001]; inline bool cmp(edge a,edge b){return a.z>b.z;} int find(int x){return fa[x]==x?x:find(fa[x]);} int main(){ n=read();m=read(); for(int i=1;i<=m;i++){ int x=read(),y=read(),z=read(); e[++tot]=(edge){x,y,z}; } sort(e+1,e+tot+1,cmp); for(int i=1;i<=n;i++)fa[i]=i; for(int i=1;i<=tot;i++){ int p=find(e[i].x),q=find(e[i].y); if(p!=q){ans+=e[i].z;cnt++;fa[p]=q;if(cnt==n){printf("%d",ans);return 0;}} } printf("-1"); return 0; }