#include <bits/stdc++.h>
#define db double
#define il inline
#define re register
#define ll long long
#define ui unsigned
#define ull ui ll
#define i128 __int128
#define pii pair<int, int>
#define fi first
#define se second
#define eb emplace_back
#define SZ(v) (int)v.size()
#define ALL(v) v.begin(), v.end()
#define mems(v, x) memset(v, x, sizeof(v))
#define memc(a, b) memcpy(a, b, sizeof(a))
#define FOR(i, L, R) for(re int i = (L); i <= (R); ++i)
#define ROF(i, R, L) for(re int i = (R); i >= (L); --i)
#define LS i << 1, l, mid
#define RS i << 1 | 1, mid + 1, r
#define popc(x) __builtin_popcount(x)
using namespace std;
#define N 20005
#define M 2019
int n; vector<pii> e[N]; bool u[N];
int dp[N], sz[N], rt, nowsz;
il void findrt(int x, int fa) {
  sz[x] = 1, dp[x] = 0;
  for(auto [y, w] : e[x]) if(y ^ fa && !u[y])
    findrt(y, x), sz[x] += sz[y], dp[x] = max(dp[x], sz[y]);
  dp[x] = max(dp[x], nowsz - sz[x]);
  if(dp[rt] > dp[x]) rt = x;
}
int ans;
int cnt[M];
vector<int> tmp;
il void dfs(int x, int fa, int s) {
  tmp.eb(s);
  for(auto [y, w] : e[x]) if(y ^ fa && !u[y])
    dfs(y, x, (s + w) % M);
}
il void solve(int x) {
  vector<int> A;
  A.eb(0), ++cnt[0];
  for(auto [y, w] : e[x]) if(!u[y]) {
    dfs(y, x, w);
    for(auto t : tmp) ans += cnt[(M - t) % M];
    for(auto t : tmp) A.eb(t), ++cnt[t];
    vector<int>().swap(tmp);
  }
  for(auto t : A) cnt[t] = 0;
}
il void divide(int x) {
  u[x] = 1, solve(x);
  for(auto [y, w] : e[x]) if(!u[y])
    nowsz = sz[y], rt = 0, findrt(y, x), divide(rt);
}
il void WORK() {
  FOR(i, 1, n)
    vector<pii>().swap(e[i]), u[i] = 0;
  FOR(i, 1, n - 1) {
    int x, y, v; cin >> x >> y >> v;
    e[x].eb(y, v), e[y].eb(x, v);
  }
  ans = 0;
  nowsz = n, dp[rt = 0] = 1e9, findrt(1, 0), divide(rt);
  cout << ans << "\n";
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  while(cin >> n) WORK();
  cerr << 1.0 * clock() / CLOCKS_PER_SEC;
  return 0;
}