#include #define For(i, a, b) for (int(i) = (int)(a); (i) < (int)(b); ++(i)) #define rFor(i, a, b) for (int(i) = (int)(a)-1; (i) >= (int)(b); --(i)) #define rep(i, n) For((i), 0, (n)) #define rrep(i, n) rFor((i), (n), 0) #define fi first #define se second using namespace std; typedef long long lint; typedef unsigned long long ulint; typedef pair pii; typedef pair pll; template bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; } template bool chmin(T &a, const T &b) { if (a > b) { a = b; return true; } return false; } template T div_floor(T a, T b) { if (b < 0) a *= -1, b *= -1; return a >= 0 ? a / b : (a + 1) / b - 1; } template T div_ceil(T a, T b) { if (b < 0) a *= -1, b *= -1; return a > 0 ? (a - 1) / b + 1 : a / b; } constexpr lint mod = 1000000007; constexpr lint INF = mod * mod; constexpr int MAX = 200010; template struct modint { using i64 = int_fast64_t; i64 a; modint(const i64 a_ = 0) : a(a_) { if (a > MOD) a %= MOD; else if (a < 0) (a %= MOD) += MOD; } modint inv() { i64 t = 1, n = MOD - 2, x = a; while (n) { if (n & 1) (t *= x) %= MOD; (x *= x) %= MOD; n >>= 1; } modint ret(t); return ret; } bool operator==(const modint x) const { return a == x.a; } bool operator!=(const modint x) const { return a != x.a; } modint operator+(const modint x) const { return modint(*this) += x; } modint operator-(const modint x) const { return modint(*this) -= x; } modint operator*(const modint x) const { return modint(*this) *= x; } modint operator/(const modint x) const { return modint(*this) /= x; } modint operator^(const lint x) const { return modint(*this) ^= x; } modint &operator+=(const modint &x) { a += x.a; if (a >= MOD) a -= MOD; return *this; } modint &operator-=(const modint &x) { a -= x.a; if (a < 0) a += MOD; return *this; } modint &operator*=(const modint &x) { (a *= x.a) %= MOD; return *this; } modint &operator/=(modint x) { (a *= x.inv().a) %= MOD; return *this; } modint &operator^=(lint n) { i64 ret = 1; while (n) { if (n & 1) (ret *= a) %= MOD; (a *= a) %= MOD; n >>= 1; } a = ret; return *this; } modint operator-() const { return modint(0) - *this; } modint &operator++() { return *this += 1; } modint &operator--() { return *this -= 1; } bool operator<(const modint x) const { return a < x.a; } }; using mint = modint<1000000007>; vector fact; vector revfact; void setfact(int n) { fact.resize(n + 1); revfact.resize(n + 1); fact[0] = 1; rep(i, n) fact[i + 1] = fact[i] * mint(i + 1); revfact[n] = fact[n].inv(); for (int i = n - 1; i >= 0; i--) revfact[i] = revfact[i + 1] * mint(i + 1); } mint getC(int n, int r) { if (n < r) return 0; return fact[n] * revfact[r] * revfact[n - r]; } typedef struct UnionFindTree { vector par; UnionFindTree(int n) { par.resize(n, -1); } bool is_root(int x) { return par[x] < 0; } int find(int x) { if (is_root(x)) return x; return par[x] = find(par[x]); } int size(int x) { return -par[find(x)]; } bool unite(int x, int y) { x = find(x); y = find(y); if (x == y) return false; if (size(x) < size(y)) swap(x, y); par[x] += par[y]; par[y] = x; return true; } bool same(int x, int y) { return find(x) == find(y); } } UF; int n, m; mint X, ans; vector G[MAX]; int dfs(int v, int pv) { int ret = 1; for (auto [nv, z] : G[v]) { if (nv != pv) { int tmp = dfs(nv, v); ans += (X ^ z) * mint(tmp) * mint(n - tmp); ret += tmp; } } return ret; } int main() { scanf("%d%d%lld", &n, &m, &X.a); UF uf(n); rep(_, m) { int x, y, z; scanf("%d%d%d", &x, &y, &z); --x; --y; int sx = uf.size(x), sy = uf.size(y); if (uf.unite(x, y)) { G[x].emplace_back(y, z); G[y].emplace_back(x, z); } } dfs(0, -1); printf("%lld\n", ans.a); }