#include<bits/stdc++.h>
using namespace std;

#define int long long
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(c) (c).rbegin(),(c).rend()
#define mp make_pair
#define endl '\n'
//#define vec vector<ll>
//#define mat vector<vector<ll> >
#define fi first
#define se second
#define double long double
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
//typedef long double ld;
typedef complex<double> Complex;
const ll INF=1e9+7;
const ll MOD=998244353;
const ll inf=INF*INF;
const ll mod=MOD;
const ll MAX=200010;
const double PI=acos(-1.0);
typedef vector<vector<ll> > mat;
typedef vector<ll> vec;

vector<map<ll,pll> >ma(MAX);
vector<vector<pll> >G(MAX);
ll sum=0;
vector<ll>sz(MAX);
ll n;
void dfs(ll i,ll p,ll s){
    map<ll,pll>tmp;
    ll cnt=1;
    for(auto e:G[i]){
        if(e.fi==p)continue;
        dfs(e.fi,i,s^e.se);
        cnt+=sz[e.fi];
    }
    for(auto e:G[i]){
        if(e.fi==p)continue;
        ll z=sz[e.fi];
        sum+=ma[e.fi][s].fi*(cnt-z);
        if(ma[e.fi].size()>tmp.size()){
            swap(tmp,ma[e.fi]);
        }
        for(auto u:ma[e.fi]){
            if(u.fi!=s)sum+=u.se.fi*tmp[u.fi].se+u.se.se*tmp[u.fi].fi;
            tmp[u.fi].fi+=u.se.fi;
            tmp[u.fi].se+=u.se.se;
        }
    }
    sum+=tmp[s].se;
    sum+=(n-cnt)*tmp[s].fi;
    tmp[s].fi=1;
    tmp[s].se=cnt;
    swap(ma[i],tmp);
    sz[i]=cnt;
}

void solve(){
    cin>>n;
    rep(i,n-1){
        ll a,b,c;cin>>a>>b>>c;
        a--;b--;
        G[a].pb(mp(b,c));
        G[b].pb(mp(a,c));
    }
    dfs(0,-1,0);
    ll ans=n*(n-1)-sum;
    cout<<ans<<endl;
}

signed main(){
    //cin.tie(0);
    //ios::sync_with_stdio(false);
    solve();
}