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

typedef long long ll;
#define REP(i,n) for(int i=0,_n=(int)(n);i<_n;++i)
#define ALL(v) (v).begin(),(v).end()
#define CLR(t,v) memset(t,(v),sizeof(t))
template<class T1,class T2>ostream& operator<<(ostream& os,const pair<T1,T2>&a){return os<<"("<<a.first<<","<<a.second<< ")";}
template<class T>void chmin(T&a,const T&b){if(a>b)a=b;}
template<class T>void chmax(T&a,const T&b){if(a<b)a=b;}
#ifdef LOCAL
template<class T>void pv(T a,T b){for(T i=a;i!=b;++i)cerr<<(*i)<<" ";cerr<<endl;}
#else
template<class T>void pv(T a,T b){}
#endif

ll nextLong() { ll x; scanf("%lld", &x); return x;}

const ll MOD = 1e9 + 7;

struct mint {
  ll x;
  mint(ll x=0):x((x%MOD+MOD)%MOD){}
  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 {mint res(*this);return res+=a;}
  mint operator-(const mint a) const {mint res(*this);return res-=a;}
  mint operator*(const mint a) const {mint res(*this);return res*=a;}
  mint pow(ll b) const {
    mint res(1), a(*this);
    while (b) {
      if (b & 1) res *= a;
      a *= a;
      b >>= 1;
    }
    return res;
  }
  // 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 {mint res(*this);return res/=a;}
};
ostream& operator<<(ostream& os, const mint& a) {os << a.x; return os;}

struct UnionFind {
  vector<int> data; // 根の場合は集合の大きさ*-1、子の場合は親の番号が入る
  UnionFind(int size) : data(size, -1) { }
  bool link(int x, int y) { //新たな併合を行うとtrue
    x = root(x); y = root(y);
    if (x != y) {
      if (data[y] < data[x]) swap(x, y);
      data[x] += data[y]; data[y] = x;
    }
    return x != y;
  }
  int root(int x) { // 代表元を返す
    return data[x] < 0 ? x : data[x] = root(data[x]);
  }
  int size(int x) { // 要素xが含まれる集合の大きさ
    return -data[root(x)];
  }
  bool same(int x, int y) { // 同じ集合ならtrue
    return root(x) == root(y);
  }
  int num() { // 異なる集合の数
    int res = 0;
    REP(i, data.size()) res += root(i) == i;
    return res;
  }
};


struct Edge {
  int a, b, z;
};

vector<Edge> es;
vector< vector<int> > g;


const int MAX_N = 212345;
int sz[MAX_N];

int dfs(int cur, int prev) {
  int res = 1;
  for (int eid : g[cur]) {
    int nxt = es[eid].a ^ es[eid].b ^ cur;
    if (nxt == prev) continue;

    int c = dfs(nxt, cur);
    sz[eid] = c;
    res += c;
  }
  return res;
}


int main2() {
  int N = nextLong();
  int M = nextLong();
  ll X = nextLong();

  UnionFind uf(N);
  es.clear();
  g = vector< vector<int> >(N);
  REP(i, M) {
    int a = nextLong() - 1;
    int b = nextLong() - 1;
    int z = nextLong();
    if (uf.link(a, b)) {
      g[a].push_back(es.size());
      g[b].push_back(es.size());
      es.push_back((Edge){a, b, z});
    }
  }

  CLR(sz, 0);
  dfs(0, -1);

  mint ans = 0;
  for (int i = 0; i < (int)es.size(); i++) {
    ans += mint(sz[i]) * mint(N - sz[i]) * mint(X).pow(es[i].z);
  }
  cout << ans << endl;
  return 0;
}

int main() {

#ifdef LOCAL
  for (;!cin.eof();cin>>ws)
#endif
    main2();
  return 0;
}