#include <bits/stdc++.h>using namespace std;#define maxn 20005#define INF 0x7fffffffint n,m,sum,num,cnt,ans,L,root,t;int head[maxn],vis[maxn],d[maxn];int size[maxn],lar[maxn],flag[4];int E[maxn<<1],V[maxn<<1],W[maxn<<1];inline void in(int &now){    char Cget=getchar();now=0;    while(Cget>‘9‘||Cget<‘0‘)Cget=getchar();    while(Cget>=‘0‘&&Cget<=‘9‘)    {        now=now*10+Cget-‘0‘;        Cget=getchar();    }}inline void edge_add(int u,int v,int w){    E[++cnt]=head[u],V[cnt]=v,W[cnt]=w,head[u]=cnt;    E[++cnt]=head[v],V[cnt]=u,W[cnt]=w,head[v]=cnt;}inline int gcd(int a,int b){    return b==0?a:gcd(b,a%b);}void GetRoot(int now,int fa){    size[now]=1,lar[now]=0;    for(int i=head[now];i;i=E[i])    {        if(V[i]==fa||vis[V[i]]) continue;        GetRoot(V[i],now);        size[now]+=size[V[i]];        lar[now]=max(lar[now],size[V[i]]);    }    lar[now]=max(lar[now],sum-size[now]);    if(lar[now]<lar[root]) root=now;}void GetDeep(int now,int fa){    flag[d[now]]++;    for(int i=head[now];i;i=E[i])    {        if(vis[V[i]]||V[i]==fa)continue;        d[V[i]]=(d[now]+W[i])%3;        GetDeep(V[i],now);    }}int cal(int now,int dis){    d[now]=dis,flag[0]=flag[1]=flag[2]=0;    GetDeep(now,0);    return flag[1]*flag[2]*2+flag[0]*flag[0];}void work(int now){    ans+=cal(now,0),vis[now]=1;    for(int i=head[now];i;i=E[i])    {        if(vis[V[i]]) continue;        ans-=cal(V[i],W[i]);        root=0,sum=size[V[i]];        GetRoot(V[i],0),work(root);    }}int main(){    in(n);int u,v,w;    for(int i=1;i<n;i++)    {        in(u),in(v),in(w);        edge_add(u,v,w%3);    }    sum=n,lar[0]=n+1;    GetRoot(1,0),work(root);    t=gcd(ans,n*n);    printf("%d/%d\n",ans/t,n*n/t);    return 0;}