#include<cstdio>
#include<algorithm>
#include<cstring>
#define maxn 20010
using namespace std;
struct LINK{int to,next,v;
}e[maxn*2];
int deep[maxn],Distance[maxn],Maxsize[maxn],size[maxn],temp,tot,head[maxn],vis[maxn],root,k,ans[3],an;
inline char Getchar(){static char BUF[16384],*S=BUF,*T=BUF;return(S==T)&&(T=(S=BUF)+fread(BUF,1,16384,stdin),S==T)?EOF:*S++;
}
inline int read(){int w=0;char c=Getchar();while(c<'0'||c>'9') c=Getchar();while(c>='0'&&c<='9'){w=w*10+c-48;c=Getchar();}return w;
}
//inline int gcd(int x,int y){
//    int t;
//  while(y){
//      t=x%y;
//      x=y;y=t;
//  }
//  return x;
//}
inline int gcd(int a,int b)
{  return b==0?a:gcd(b,a%b);
}
inline void add(int x,int y,int w){tot++;e[tot].to=y;e[tot].next=head[x];e[tot].v=w;head[x]=tot;
}
inline void getroot(int x,int fa){size[x]=1;Maxsize[x]=0;for(int i=head[x];i;i=e[i].next){if(!vis[e[i].to]&&e[i].to!=fa){getroot(e[i].to,x);size[x]+=size[e[i].to];Maxsize[x]=max(Maxsize[x],size[e[i].to]);}}Maxsize[x]=max(Maxsize[x],temp-size[x]);if(Maxsize[x]<Maxsize[root]) root=x;
}
inline void getdeep(int x,int fa){ans[Distance[x]]++;for(int i=head[x];i;i=e[i].next){if(!vis[e[i].to]&&e[i].to!=fa){Distance[e[i].to]=(Distance[x]+e[i].v)%3;getdeep(e[i].to,x);}}
}
inline int answer(int x,int w){memset(ans,0,sizeof(ans));Distance[x]=w;getdeep(x,0);return ans[0]*ans[0]+ans[1]*ans[2]*2;
}
inline void solve(int x){an+=answer(x,0);vis[x]=1;for(int i=head[x];i;i=e[i].next){if(!vis[e[i].to]){an-=answer(e[i].to,e[i].v);temp=size[e[i].to];root=0;getroot(e[i].to,0);solve(root);}}
}
int main(){int n,i,x,y,v;n=read();for(i=1;i<n;i++){x=read();y=read();v=read();add(x,y,v%3);add(y,x,v%3);}Maxsize[0]=n+1;temp=n;getroot(1,0);solve(root);int l=gcd(n*n,an);printf("%d/%d",an/l,n*n/l);return 0;
}