#include<bits/stdc++.h>
using namespace std;
int n,m,p,N;
vector<pair<int,int>>g[200005];
int dfn[200005],low[200005],tot=0;
stack<int>st;
vector<pair<int,int>>gg[400005];
map<long long,int>mp;
void jia(int u,int v,int w){
	if(u>v)swap(u,v);
	mp[1ll*u*(n+1)+v]=w;
}
int cha(int u,int v){
	if(u>v)swap(u,v);
	return mp[1ll*u*(n+1)+v];
}
void dfs0(int x,int la){
	dfn[x]=low[x]=++tot;
	st.emplace(x);
	for(auto pi:g[x]){
		int cu=pi.first,c2=pi.second;
		if(cu==la)continue;
		if(!dfn[cu]){
			dfs0(cu,x);
			low[x]=min(low[x],low[cu]);
			if(low[cu]>=dfn[x]){
				vector<int>vc;
				while(st.size()){
					int u=st.top();st.pop();
					vc.emplace_back(u);
					if(u==cu)break;
				}
				int sz=vc.size();
				if(sz==1){
					gg[x].emplace_back(cu,c2);
				}else{
					++N;gg[x].emplace_back(N,c2);
					for(int i=sz-1;i>=0;--i){
						int u=vc[i],v=(i>0?vc[i-1]:x);
						gg[N].emplace_back(u,cha(u,v));
					}
				}
			}
		}else{
			low[x]=min(low[x],dfn[cu]);
		}
	}
}
long long f0[400005],f1[400005],f2[400005];
__int128 f[200005][2][2];
inline long long get(int x,int y){
	return y==0?f0[x]:y==1?f1[x]:f2[x];
}
__int128 ff[400005],f3[400005];
int h;
void gai(long long x){
	for(int i=0;i<=h;++i)f3[i+1]=ff[i]+x;
	ff[h+1]=-1e25;
	for(int i=1;i<=h+1;++i)ff[i]=max(ff[i],f3[i]);
	++h;
}
void gai2(long long x,long long y){
	for(int i=0;i<=h;++i)f3[i+2]=ff[i]+y;
	f3[1]=ff[0]+x;
	for(int i=1;i<=h;++i)f3[i+1]=max(f3[i+1],ff[i]+x);
	ff[h+1]=ff[h+2]=-1e25;
	for(int i=1;i<=h+2;++i)ff[i]=max(ff[i],f3[i]);
	++h;++h;
}
void dfs1(int x,int la,int c2){
	for(auto pi:gg[x]){
		int cu=pi.first,cc=pi.second;
		dfs1(cu,x,cc);
	}
	if(x<=n){
		long long fh=0;
		h=0;ff[0]=0;
		for(auto pi:gg[x]){
			int cu=pi.first,cc=pi.second;
			fh+=f0[cu];
			if(cu<=n)gai(f1[cu]-f0[cu]-cc);
			else{
				gai2(f1[cu]-f0[cu],f2[cu]-f0[cu]);
			}
		}
		int d=g[x].size();
		f0[x]=fh;f1[x]=fh+1ll*d*(d-1)*p;f2[x]=fh+2ll*d*(d-2)*p;
		for(int i=0;i<h;++i){
			__int128 he=ff[i+1];
			f0[x]=max((__int128)f0[x],fh+he+1ll*(i+1)*(d-i-1)*d*p);
			f1[x]=max((__int128)f1[x],fh+he+1ll*(i+2)*(d-i-2)*d*p);
			f2[x]=max((__int128)f2[x],fh+he+1ll*(i+3)*(d-i-3)*d*p);
		}
	}else{
		int m=gg[x].size();
		for(int i=0;i<=m;++i)memset(f[i],-63,sizeof(f[i]));
		f[0][0][0]=0;f[0][1][1]=-c2;
		for(int i=0;i<m;++i){
			for(int j=0;j<2;++j)for(int k=0;k<2;++k){
				for(int s=0;s<2;++s){
					f[i+1][j][s]=max(f[i+1][j][s],f[i][j][k]+get(gg[x][i].first,k+s)-gg[x][i].second*s);
				}
			}
		}
		f0[x]=f[m][0][0];f2[x]=f[m][1][1];
		f1[x]=max(f[m][0][1],f[m][1][0]);
	}
}
int main(){
	scanf("%d%d%d",&n,&m,&p);
	for(int i=1;i<=m;++i){
		int u,v,w;
		scanf("%d%d%d",&u,&v,&w);w*=2;
		g[u].emplace_back(v,w);
		g[v].emplace_back(u,w);
		jia(u,v,w);
	}
	N=n;dfs0(1,0);
	dfs1(1,0,0);
	printf("%lld\n",f0[1]/2);
	return 0;
}