#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <set>
#include <map>

using namespace std;
typedef long long ll;

struct UnionFind {
  vector<int> data;
  UnionFind(int size) : data(size, -1) { }
  bool unionSet(int x, int y) {
    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;
  }
  bool findSet(int x, int y) {
    return root(x) == root(y);
  }
  int root(int x) {
    return data[x] < 0 ? x : data[x] = root(data[x]);
  }
  int size(int x) {
    return -data[root(x)];
  }
};

const ll MOD = 1000000007;

class ModInt{
    public:
    ll v;
    ModInt(ll _v = 0){
        v = _v;
    }
    ModInt operator+(ll n){
        return ModInt((v+n)%MOD);
    }
    ModInt operator-(ll n){
        return ModInt((v-n+MOD)%MOD);
    }
    ModInt operator*(ll n){
        return ModInt((v*n)%MOD);
    }
    ModInt operator/(ll n){
        return ModInt((ModInt(n).inv()*v).v%MOD);
    }

    void operator+=(ll n){
        v = (v+n)%MOD;
    }
    void operator-=(ll n){
        v = (v-n+MOD)%MOD;
    }
    void operator*=(ll n){
        v = (v*n)%MOD;
    }
    
    
    ModInt operator+(ModInt n){
        return ModInt((v+n.v)%MOD);
    }
    ModInt operator-(ModInt n){
        return ModInt((v-n.v+MOD)%MOD);
    }
    ModInt operator*(ModInt n){
        return ModInt((v*n.v)%MOD);
    }
    ModInt operator/(ModInt n){
        return ModInt((n.inv()*v).v%MOD);
    }

    void operator+=(ModInt n){
        v = (v+n.v)%MOD;
    }
    void operator-=(ModInt n){
        v = (v-n.v+MOD)%MOD;
    }
    void operator*=(ModInt n){
        v = (v*n.v)%MOD;
    }

    void operator=(ModInt n){
        v = n.v;
    }
    void operator=(ll n){
        v = n;
    }

    ModInt inv(){
        if(v == 1) return ModInt(1);
        else return ModInt(MOD-ModInt(MOD%v).inv().v*(MOD/v)%MOD);
    }
};

ostream& operator<<(ostream& os, const ModInt& m){
    os << m.v;
    return os;
}

istream & operator >> (istream &in,  ModInt &m){
    in >> m.v;
    return in;
}

ModInt pow(ModInt a, ll n) {
	ModInt ans = 1;
	ModInt tmp = a;
	for (int i = 0; i <= 60; i++) {
		ll m = (ll)1 << i;
		if (m & n) {
		ans *= tmp;
		}
		tmp *= tmp;
	}
	return ans;
}


ll N, M, X;
ModInt ans = 0;
int x[200000], y[200000], z[200000];
bool used[200000];

int depth[200000];
int ch[200000];
vector<int> G[200000];
bool used_dfs[200000];

void dfs(int v){
    used_dfs[v] = true;
    ch[v] = 1;
    for(int to: G[v]){
        if(!used_dfs[to]) {
            dfs(to);
            ch[v] += ch[to];
        }
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    cin >> N >> M >> X;
    UnionFind uf(N);
    for(int i = 0; i < M; i++){
        cin >> x[i] >> y[i] >> z[i]; x[i]--; y[i]--;
        int rx = uf.root(x[i]), ry = uf.root(y[i]);
        if(rx != ry){
            used[i] = true;
            G[x[i]].push_back(y[i]);
            G[y[i]].push_back(x[i]);
            uf.unionSet(x[i], y[i]);
        }
    }
    dfs(0);
    for(int i = 0; i < M; i++){
        if(used[i]){
            if(ch[x[i]] > ch[y[i]]) swap(x[i], y[i]);
            ans += pow(X, z[i])*ch[x[i]]*(N-ch[x[i]]);
        }
    }
    cout << ans << endl;
}