#include<bits/stdc++.h>

using namespace std;
using ll = long long;

#define MOD 1000000007
template<int mod>
struct ModInt{
   int x;
   ModInt():x(0){}
   ModInt(long long y):x(y>=0?y%mod:(mod-(-y)%mod)%mod){}
   ModInt &operator+=(const ModInt &p){
	   if((x+=p.x)>=mod)x-=mod;
	   return *this;
   }
   ModInt &operator-=(const ModInt &p){
	   if((x+=mod-p.x)>=mod)x-=mod;
	   return *this;
   }
   ModInt &operator*=(const ModInt &p){
	   x=(int)(1LL*x*p.x%mod);
	   return *this;
   }
   ModInt &operator/=(const ModInt &p){
	   *this*=p.inverse();
	   return *this;
   }
   ModInt &operator^=(long long p){
	   ModInt res = 1;
	   for (; p; p >>= 1) {
		   if (p & 1) res *= *this;
		   *this *= *this;
	   }
	   return *this = res;
   }
   ModInt operator-()const{return ModInt(-x);}
   ModInt operator+(const ModInt &p)const{return ModInt(*this)+=p;}
   ModInt operator-(const ModInt &p)const{return ModInt(*this)-=p;}
   ModInt operator*(const ModInt &p)const{return ModInt(*this)*=p;}
   ModInt operator/(const ModInt &p)const{return ModInt(*this)/=p;}
   ModInt operator^(long long p)const{return ModInt(*this)^=p;}
   bool operator==(const ModInt &p)const{return x==p.x;}
   bool operator!=(const ModInt &p)const{return x!=p.x;}
   explicit operator int() const { return x; }
   ModInt operator=(const int p) {x = p; return ModInt(*this);}
   ModInt inverse()const{
	   int a=x,b=mod,u=1,v=0,t;
	   while(b>0){
		   t=a/b;
		   a-=t*b;
		   std::swap(a,b);
		   u-=t*v;
		   std::swap(u,v);
	   }
	   return ModInt(u);
   }
   friend std::ostream &operator<<(std::ostream &os,const ModInt<mod> &p){
	   return os<<p.x;
   }
   friend std::istream &operator>>(std::istream &is,ModInt<mod> &a){
	   long long x;
	   is>>x;
	   a=ModInt<mod>(x);
	   return (is);
   }
};
typedef ModInt<MOD> mint;

class UnionFind{
  private:
	vector<int> data;

  public:
	UnionFind(int n) : data(n,-1) {}
	int root(int i) { return data[i] < 0 ? i : data[i] = root(data[i]); }
	int size(int i) { return -data[root(i)]; }
	bool same(int x, int y) {return root(x) == root(y); }
	bool connected() {return size(0) == (int)data.size(); }

	bool unit(int i,int j){
		i = root(i);
		j = root(j);
		if(i != j){
			data[i] += data[j];
			data[j] = i;
		}
		return i != j;
	}
};

int n, m, x;
vector<vector<pair<int,int>>> hen;
map<pair<int,int>,int> mp;
mint ans = 0;

int dfs(int v, int par) {
	int sum = 0;
	for(auto i : hen[v]) {
		if(i.first == par)continue;
		sum += dfs(i.first, v);
	}
	sum++;
	int exp = mp[{v, par}];
	ans += (mint(x)^exp) * (sum) * (n - sum);
	return sum;
}


int main()
{
	cin >> n >> m >> x;
	UnionFind uni(n);
	hen.resize(n);
	for(int i = 0; i < m; i++) {
		int a, b, c; cin >> a >> b >> c; a--, b--;
		if(uni.same(a, b))continue;
		uni.unit(a,b);
		mp[{a,b}] = mp[{b,a}] = c;
		hen[a].push_back({b,c});
		hen[b].push_back({a,c});
	}
	dfs(0, -1);
	cout << ans << endl;
}