#include <bits/stdc++.h>
#define FOR(i, a, n) for(ll i = (ll)a; i < (ll)n; i++)
#define FORR(i, n) for(ll i = (ll)n - 1LL; i >= 0LL; i--)
#define rep(i, n) FOR(i, 0, n)
#define ALL(x) begin(x), end(x)
using namespace std;
using ll = long long;
constexpr ll Mod = 998244353;
constexpr ll mod = 1e9 + 7;
constexpr ll inf = 1LL << 60;
const double PI = acos(-1);
template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) {
    return a < b && (a = b, true);
}
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) {
    return a > b && (a = b, true);
}
/*-------------------------------------------*/

template <int M> class ModInt {
    int x;

  public:
    constexpr ModInt() : x(0) {}
    constexpr ModInt(int64_t y) : x(y >= 0 ? y % M : (M - (-y) % M) % M) {}
    constexpr ModInt &operator+=(const ModInt p) {
        if((x += p.x) >= M) x -= M;
        return *this;
    }
    constexpr ModInt &operator-=(const ModInt p) {
        if((x += M - p.x) >= M) x -= M;
        return *this;
    }
    constexpr ModInt &operator*=(const ModInt p) {
        x = (int)(1LL * x * p.x % M);
        return *this;
    }
    constexpr ModInt &operator/=(const ModInt p) {
        *this *= p.inverse();
        return *this;
    }
    constexpr ModInt operator-() const { return ModInt(-x); }
    constexpr ModInt operator+(const ModInt p) const {
        return ModInt(*this) += p;
    }
    constexpr ModInt operator-(const ModInt p) const {
        return ModInt(*this) -= p;
    }
    constexpr ModInt operator*(const ModInt p) const {
        return ModInt(*this) *= p;
    }
    constexpr ModInt operator/(const ModInt p) const {
        return ModInt(*this) /= p;
    }
    constexpr bool operator==(const ModInt p) const { return x == p.x; }
    constexpr bool operator!=(const ModInt p) const { return x != p.x; }
    constexpr ModInt inverse() const {
        int a = x, b = M, u = 1, v = 0, t = 0;
        while(b > 0) {
            t = a / b;
            swap(a -= t * b, b);
            swap(u -= t * v, v);
        }
        return ModInt(u);
    }
    constexpr ModInt pow(int64_t k) const {
        ModInt ret(1), mul(x);
        while(k > 0) {
            if(k & 1) ret *= mul;
            mul *= mul;
            k >>= 1;
        }
        return ret;
    }
    constexpr friend ostream &operator<<(ostream &os, const ModInt &p) {
        return os << p.x;
    }
    constexpr friend istream &operator>>(istream &is, ModInt &a) {
        int64_t t = 0;
        is >> t;
        a = ModInt(t);
        return (is);
    }
};
using mint = ModInt<mod>;

class UnionFind {
    vector<int> par;
    int c;

  public:
    UnionFind(int n) : par(n, -1), c(n) {}
    int find(int x) { return par[x] < 0 ? x : par[x] = find(par[x]); }
    int size(int x) { return -par[find(x)]; }
    int count() const { return c; }
    bool same(int x, int y) { return find(x) == find(y); }
    bool unite(int x, int y) {
        if((x = find(x)) == (y = find(y))) return false;
        if(par[x] < par[y]) swap(x, y);
        par[y] += par[x];
        par[x] = y;
        return c--;
    }
};

int n, m;
mint x, ans;

vector<pair<int, mint>> g[200009];

int sz[200009];

void dfs(int v, int p) {
    sz[v] = 1;
    for(auto [u, cost] : g[v]) {
        if(p != u) {
            dfs(u, v);
            ans += cost * sz[u] * (n - sz[u]);
            sz[v] += sz[u];
        }
    }
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    cin >> n >> m >> x;
    UnionFind uf(n);
    rep(i, m) {
        int a, b, z;
        cin >> a >> b >> z;
        a--;
        b--;
        if(uf.unite(a, b)) {
            mint cost = x.pow(z);
            g[a].emplace_back(b, cost);
            g[b].emplace_back(a, cost);
        }
    }

    dfs(0, -1);

    cout << ans << endl;

    return 0;
}