#line 1 "a.cpp"
#include<iostream>
#include<vector>
using namespace std;
#line 3 "/home/kotatsugame/library/math/modint.cpp"
#include<utility>
template<int m>
struct modint{
	unsigned int x;
	constexpr modint()noexcept:x(){}
	constexpr modint(long long _x)noexcept:x((_x%=m)<0?_x+m:_x){}
	constexpr unsigned int val()const noexcept{return x;}
	constexpr modint&operator++()noexcept{if(++x==m)x=0;return*this;}
	constexpr modint&operator--()noexcept{if(x==0)x=m;--x;return*this;}
	constexpr modint operator++(int)noexcept{modint res=*this;++*this;return res;}
	constexpr modint operator--(int)noexcept{modint res=*this;--*this;return res;}
	constexpr modint&operator+=(const modint&a)noexcept{x+=a.x;if(x>=m)x-=m;return*this;}
	constexpr modint&operator-=(const modint&a)noexcept{if(x<a.x)x+=m;x-=a.x;return*this;}
	constexpr modint&operator*=(const modint&a)noexcept{x=(unsigned long long)x*a.x%m;return*this;}
	constexpr modint&operator/=(const modint&a)noexcept{return*this*=a.inv();}
	constexpr modint operator+()const noexcept{return*this;}
	constexpr modint operator-()const noexcept{return modint()-*this;}
	constexpr modint pow(long long n)const noexcept
	{
		if(n<0)return pow(-n).inv();
		modint x=*this,r=1;
		for(;n;x*=x,n>>=1)if(n&1)r*=x;
		return r;
	}
	constexpr modint inv()const noexcept
	{
		int s=x,t=m,x=1,u=0;
		while(t)
		{
			int k=s/t;
			s-=k*t;
			swap(s,t);
			x-=k*u;
			swap(x,u);
		}
		return modint(x);
	}
	constexpr modint operator+(const modint&a)const noexcept{return modint(*this)+=a;}
	constexpr modint operator-(const modint&a)const noexcept{return modint(*this)-=a;}
	constexpr modint operator*(const modint&a)const noexcept{return modint(*this)*=a;}
	constexpr modint operator/(const modint&a)const noexcept{return modint(*this)/=a;}
	constexpr bool operator==(const modint&a)const noexcept{return x==a.x;}
	constexpr bool operator!=(const modint&a)const noexcept{return x!=a.x;}
	friend ostream&operator<<(ostream&os,const modint&a){return os<<a.x;}
	friend istream&operator>>(istream&is,modint&a){long long v;is>>v;a=modint(v);return is;}
};
#line 2 "/home/kotatsugame/library/datastructure/UF.cpp"
struct UF{
	int n;
	vector<int>parent,rank;
	UF(int n_=0):n(n_),parent(n_),rank(n_,1)
	{
		for(int i=0;i<n_;i++)parent[i]=i;
	}
	int find(int a){return parent[a]!=a?parent[a]=find(parent[a]):a;}
	bool same(int a,int b){return find(a)==find(b);}
	bool unite(int a,int b)
	{
		a=find(a),b=find(b);
		if(a==b)return false;
		if(rank[a]<rank[b])
		{
			parent[a]=b;
			rank[b]+=rank[a];
		}
		else
		{
			parent[b]=a;
			rank[a]+=rank[b];
		}
		return true;
	}
	int size(int a){return rank[find(a)];}
};
#line 6 "a.cpp"
using mint=modint<(int)1e9+7>;
int N,M;
mint X;
vector<int>G[2<<17];
vector<pair<pair<int,int>,int> >E;
int depth[2<<17],ch[2<<17];
int dfs(int u,int p,int d)
{
	depth[u]=d;
	ch[u]=1;
	for(int v:G[u])if(v!=p)
	{
		ch[u]+=dfs(v,u,d+1);
	}
	return ch[u];
}
main()
{
	cin>>N>>M>>X;
	UF uf(N);
	for(int i=0;i<M;i++)
	{
		int x,y,z;cin>>x>>y>>z;
		x--,y--;
		if(uf.unite(x,y))
		{
			G[x].push_back(y);
			G[y].push_back(x);
			E.push_back(make_pair(make_pair(x,y),z));
		}
	}
	dfs(0,-1,0);
	mint ans=0;
	for(pair<pair<int,int>,int>e:E)
	{
		int u=e.first.first,v=e.first.second;
		if(depth[u]<depth[v])u=v;
		ans+=X.pow(e.second)*ch[u]*(N-ch[u]);
	}
	cout<<ans<<endl;
}