#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define ll long long
#define rep(i,n) for(ll i=0;i<(n);i++)
#define pll pair<ll,ll>
#define pii pair<int,int>
#define pq priority_queue
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define endl '\n'
#define ios ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define lb(c,x) distance(c.begin(),lower_bound(all(c),x))
#define ub(c,x) distance(c.begin(),upper_bound(all(c),x))

using namespace std;

inline int topbit(unsigned long long x){
	return x?63-__builtin_clzll(x):-1;
}

inline int popcount(unsigned long long x){
	return __builtin_popcountll(x);
}

inline int parity(unsigned long long x){//popcount%2
	return __builtin_parity(x);
}



template<class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;}return 0;}

const ll INF=1e15;

const ll 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;}
};
istream& operator>>(istream& is, mint& a) { return is >> a.x;}
ostream& operator<<(ostream& os, const mint& a) { return os << a.x;}
// combination mod prime
// https://www.youtube.com/watch?v=8uowVvQ_-Mo&feature=youtu.be&t=1619
struct combination {
  vector<mint> fact, ifact;
  combination(ll n):fact(n+1),ifact(n+1) {
    assert(n < mod);
    fact[0] = 1;
    for (ll i = 1; i <= n; ++i) fact[i] = fact[i-1]*i;
    ifact[n] = fact[n].inv();
    for (ll i = n; i >= 1; --i) ifact[i-1] = ifact[i]*i;
  }
  mint operator()(ll n, ll k) {
    if (k < 0 || k > n) return 0;
    return fact[n]*ifact[k]*ifact[n-k];
  }
  mint p(ll n, ll k) {
    return fact[n]*ifact[n-k];
  }
} c(1000005);

class DisjointSet{
    public:
    vector<ll> rank,p,sz;
    DisjointSet(){}
    DisjointSet(ll size){ //作られうる木の頂点数の最大値を入れる。
        rank.resize(size,0);
        p.resize(size,0);
        sz.resize(size,0);
        rep(i,size) makeSet(i);
    }
    void makeSet(ll x){ //xだけが属する木を作る。
        p[x]=x;
        rank[x]=0;
    }
    bool same(ll x,ll y){ //xとyが同じ木に属するかどうか
        return findSet(x)==findSet(y);
    }
    void unite(ll x, ll y){
        link(findSet(x),findSet(y));
    }
    void link(ll x, ll y){ //rankが大きい方の根に小さい方の根をつける。
        if(rank[x]>rank[y]){
            p[y]=x;
        }
        else{
            p[x]=y;
            if(rank[x]==rank[y]){
                rank[y]++; //xとyの木のrankが同じであれば、統合するとrankが1増える。
            }
        }
        sz[x]+=sz[y];
        sz[y]=sz[x];
    }
    ll findSet(ll x){ //xが属する木の根の番号を返す
        if(x!=p[x]){
            p[x]=findSet(p[x]);
        }
        return p[x];
    }
};

vector<vector<pll>> to;

vector<ll> memo;

ll dfs(ll v,ll p=-1){
    ll res=1;
    for(auto q:to[v]){
        if(q.fi==p) continue;
        res+=dfs(q.fi,v);
    }
    return memo[v]=res;
}

int main(){
    ll n,m;
    mint X;
    cin >> n >> m >> X;
    DisjointSet ds=DisjointSet(n+1);
    vector<pair<ll,pll>> edges(m);
    memo.resize(n);
    to=vector<vector<pll>>(n);
    vector<ll> not_need(m);
    rep(i,m){
        cin >> edges[i].se.fi >> edges[i].se.se >> edges[i].fi;
        edges[i].se.fi--;
        edges[i].se.se--;
        if(ds.same(edges[i].se.fi,edges[i].se.se)){
            not_need[i]=1;
        }
        else{
            ds.unite(edges[i].se.fi,edges[i].se.se);
        }
    }
    
    rep(i,m){
        if(not_need[i]) continue;
        to[edges[i].se.fi].push_back({edges[i].se.se,edges[i].fi});
        to[edges[i].se.se].push_back({edges[i].se.fi,edges[i].fi});
    }
    ll d=dfs(0LL);
    mint ans=0;
    rep(i,m){
        if(not_need[i]) continue;
        mint val=X.pow(edges[i].fi);
        ll s=memo[edges[i].se.fi];
        ll t=memo[edges[i].se.se];
        if(s<t) swap(s,t);
        mint u=t;
        ans+=u*(n-u.x)*val;
        
    }
    cout << ans << endl;
    return 0;
}