#include<bits/stdc++.h>

using namespace std;

#define inf 0x7fffffff

const int M = 1e5+;

int siz[M],f[M],head[M],vis[M],ans,cnt,t[M],sum,root,d[M];

struct node{

    int to,next,w;

}e[M<<];

void init(){

    ans = ;

    cnt = ;

    memset(vis,,sizeof(vis));

    memset(head,,sizeof(head));

}

void add(int u,int v,int w){

    e[++cnt].to = v; e[cnt].w = w; e[cnt].next = head[u]; head[u] = cnt;

}

void get_root(int u,int fa){

    siz[u] = ; f[u] = ;

    for(int i = head[u];i;i = e[i].next){

        int v = e[i].to;

        if(v != fa&&!vis[v]){

            get_root(v,u);

            siz[u] += siz[v];

            f[u] = max(f[u],siz[v]);

        }

    }

    f[u] = max(f[u],sum - siz[u]);

    if(f[u] < f[root]) root = u;

    return ;

}

void get_dis(int u,int fa){

    t[d[u]]++;

    for(int i = head[u];i;i = e[i].next){

        int v = e[i].to;

        if(v != fa&& !vis[v]){

            d[v] = (d[u] + e[i].w)%;

            get_dis(v,u);

        }

    }

    return ;

}

int cal(int u,int c){

    t[] = t[] = t[] = ;

    d[u] = c;

    get_dis(u,);

    return t[]*t[]*+t[]*t[];

}

void solve(int v){

    ans += cal(v,); vis[v] = ;

    for(int i = head[v];i;i = e[i].next){

        int v = e[i].to;

        if(!vis[v]){

            ans -= cal(v,e[i].w);

            sum = siz[v];

            root = ;

            get_root(v,);

            solve(root);

        }

    }

}

int main()

{

    ios::sync_with_stdio();

    cin.tie(); cout.tie();

    int m,u,v,w,n;

    cin>>n;

    init();

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

        cin>>u>>v>>w;

        w%=;

        add(u,v,w);

        add(v,u,w);

    }

    f[] = inf;

    sum = n;

    root = ;

    get_root(,);

    solve(root);

    int x = __gcd(ans,n*n);

    cout<<ans/x<<"/"<<n*n/x<<endl;

    return ;

}