#include<cstdio>

#include<algorithm>

using namespace std;

struct data{int f,t,d;}a[];

int n,fa[],siz[]; long long ans;

inline bool cmp(const data &A,const data &B) {return A.d<B.d;}

inline int find(int x) {return x==fa[x] ? x:fa[x]=find(fa[x]);}

int main(){

    scanf("%d",&n);

    for(int i=;i<n;++i){

        scanf("%d%d%d",&a[i].f,&a[i].t,&a[i].d);

        ans+=a[i].d; fa[i]=i; siz[i]=;

    }fa[n]=n; siz[n]=;

    sort(a+,a+n,cmp); //按边排序

    for(int i=;i<n;++i){

        int r1=find(a[i].f),r2=find(a[i].t);

        ans+=1LL*(siz[r1]*siz[r2]-)*(a[i].d+); //每2个不同块的点都连起来

        fa[r2]=r1; siz[r1]+=siz[r2]; //合并

    }

    printf("%lld",ans);

    return ;

}