#include<bits/stdc++.h>
#define ll long long
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rof(i,a,b) for(int i=(a);i>=(b);--i)
using namespace std;
const int Maxn=2e4,P=2019;

int n,f[Maxn+5][P+5]; ll ans;
vector<pair<int,int>> v[Maxn+5];

inline void dfs(int x,int fa,int d)
{
    f[x][d]++; for(auto [y,z]:v[x]) if(y!=fa) dfs(y,x,(d+z)%P);
    for(auto [y,z]:v[x]) if(y!=fa)
    {
        For(a,0,P-1) if(f[x][a]) ans+=1ll*f[x][a]*f[y][(P+d*2-a)%P];
        For(a,0,P-1) f[x][a]+=f[y][a];
    }
}
inline void Solve()
{
    For(i,1,n) vector<pair<int,int>>().swap(v[i]),memset(f[i],0,sizeof(f[i]));
    For(i,1,n-1)
    {
        int a,b,c; cin>>a>>b>>c;
        v[a].emplace_back(b,c),v[b].emplace_back(a,c);
    } dfs(1,0,0); cout<<ans<<endl; ans=0;
}

int main()
{
    // freopen("1.in","r",stdin);

    while(cin>>n) Solve();
    return 0;
}