#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef long double ld;
typedef pair<int,int> P;
typedef tuple<int,int,int> TP;
constexpr int mod = 1e9+7;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) { (x *= a.x) %= mod; return *this;}
  mint operator+(const mint a) const { return mint(*this) += a;}
  mint operator-(const mint a) const { return mint(*this) -= a;}
  mint operator*(const mint a) const { return mint(*this) *= a;}
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }
 
  // for prime mod
  mint inv() const { return pow(mod-2);}
  mint& operator/=(const mint a) { return *this *= a.inv();}
  mint operator/(const mint a) const { return mint(*this) /= a;}
};

struct UnionFind{
  vector<int> data;
  int __size;
  UnionFind(int sz) {
  data.assign(sz, -1);
  __size = sz;
  }
 
  bool unite(int x, int y) {
    x = find(x), y = find(y);
    if(x == y) return (false);
    if(data[x] > data[y]) swap(x, y);//親は負でサイズを保存
    __size--;
    data[x] += data[y];
    data[y] = x;
    return (true);
  }
 
  int find(int k) {
    if(data[k] < 0) return (k);
    return (data[k] = find(data[k]));
  }

  bool same(int x, int y){
    return find(x) == find(y);
  }
 
  int size(int k) {
    return (-data[find(k)]);
  }

  int union_count() {
    return (__size);
  }
};

int main() {
  int n, m, x;
  cin >> n >> m >> x;
  UnionFind uf(n);
  vector<TP> edge;
  rep(i,m) {
    int x, y, z;
    cin >> x >> y >> z;
    x--; y--;
    edge.emplace_back(make_tuple(z, x, y));
  }

  sort(edge.begin(), edge.end());
  vector<vector<int>> g(n);
  vector<TP> mst;
  for (int i = 0; i < m; i++) {
    int u, v, c;
    tie(c, u, v) = edge[i];
    if (uf.same(u, v)) continue;
    uf.unite(u, v);
    mst.emplace_back(edge[i]);
    g[u].emplace_back(v);
    g[v].emplace_back(u);
  }

  vector<int> dp(n, 0);
  mint res = 0;

  auto dfs = [&](auto& f, int u = 0, int p = -1)->void{
    dp[u] = 1;
    for (auto v : g[u]) {
      if (v == p) continue;
      f(f, v, u);
      dp[u] += dp[v];
    }
  };
  dfs(dfs);

  for (auto e : mst) {
    int u, v, c;
    tie(c, u, v) = e;
    mint cost = mint(x).pow(c);
    int cnt = min(dp[u], dp[v]);
    res += cost * cnt * (n - cnt); 
  }

  cout << res.x << endl;
  return 0;
}