#include <bits/stdc++.h>
#include <unordered_map>
#define debug(a, b) printf("%s = %d\n", a, b);
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> PII;
clock_t startTime, endTime;
//Fe~Jozky
const ll INF_ll= 1e18;
const int INF_int= 0x3f3f3f3f;
void read(){};
template <typename _Tp, typename... _Tps> void read(_Tp& x, _Tps&... Ar)
{
    x= 0;
    char c= getchar();
    bool flag= 0;
    while (c < '0' || c > '9')
        flag|= (c == '-'), c= getchar();
    while (c >= '0' && c <= '9')
        x= (x << 3) + (x << 1) + (c ^ 48), c= getchar();
    if (flag)
        x= -x;
    read(Ar...);
}
template <typename T> inline void write(T x)
{
    if (x < 0) {
        x= ~(x - 1);
        putchar('-');
    }
    if (x > 9)
        write(x / 10);
    putchar(x % 10 + '0');
}
void rd_test()
{
#ifdef LOCAL
    startTime= clock();
    freopen("in.txt", "r", stdin);
#endif
}
void Time_test()
{
#ifdef LOCAL
    endTime= clock();
    printf("\nRun Time:%lfs\n", (double)(endTime - startTime) / CLOCKS_PER_SEC);
#endif
}
const int maxn= 1e5 + 9;
vector<PII> vec[maxn];
int sz[maxn];
int dis[maxn];
int son[maxn];
int Son;
int num[3];
int ans= 0;
void dfs_son(int u, int fa)
{
    sz[u]= 1;
    for (auto it : vec[u]) {
        int v= it.first;
        int w= it.second;
        if (v == fa)
            continue;
        dis[u]= dis[fa] + w;
        dfs_son(v, u);
        sz[u]+= sz[v];
        if (sz[v] > sz[son[u]])
            son[u]= v;
    }
}
void cal(int u, int fa, int LCA)
{
    int x= ((dis[LCA] - dis[u] + 3) % 3 + 3) % 3;
    ans+= num[x];
    for (auto it : vec[u]) {
        int v= it.first;
        if (v != fa && v != son[u])
            cal(v, u, LCA);
    }
}
void add(int u, int fa, int val, int LCA)
{
    int Dis= (dis[u] - dis[LCA]) % 3;
    num[Dis]+= val;
    for (auto it : vec[u]) {
        int v= it.first;
        if (v != fa && v != son[u])
            add(v, u, val, LCA);
    }
}
void work(int u, int fa, int keep)
{
    for (auto it : vec[u]) {
        int v= it.first;
        if (v != fa && v != son[u])
            work(v, u, 0);
    }
    if (son[u]) {
        work(son[u], u, 1);
        Son= son[u];
    }

    add(u, fa, 1, u);
    Son= 0;
    cal(u, fa, u);
    if (!keep) {
        add(u, fa, -1, u);
    }
}
int main()
{
    //rd_test();
    int n;
    read(n);
    for (int i= 1; i < n; i++) {
        int u, v, w;
        read(u, v, w);
        vec[u].push_back({v, w});
        vec[v].push_back({u, w});
    }
    dis[1]= 0;
    dfs_son(1, 0);
    work(1, 0, 1);
    ll a= ans + n;
    ll b= 1ll * n * n;
    ll g= __gcd(a, b);
    printf("%lld/%lld\n", a / g, b / g);
    //Time_test();
}