#include<bits/stdc++.h>
#define pii pair<int,int>
using namespace std;
struct node
{
	int x,w;
	friend bool operator<(const node &a,const node &b)
	{
		return a.w>b.w;
	}
};
priority_queue<node> q;
vector<pii> G[110005];
int dis[110005];
bool vis[110005];
int n,m,k;
int change(int id,int step)
{
	return step*n+id;
}
void Dijkstra(int s)
{
	memset(dis,0x3f,sizeof(dis));
	for(int i=0;i<=k;i++)dis[change(s,i)]=0,q.push({change(s,i),-1});
	while(q.size())
	{
		node t=q.top();q.pop();
		int x=t.x;
		if(vis[x])continue;
		vis[x]=1;
		for(auto [y,z]:G[x])
			if(dis[y]>dis[x]+z)
			{
				dis[y]=dis[x]+z;
				q.push({y,dis[y]});
			}
	}
}
signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	cin>>n>>m>>k;
	while(m--)
	{
		int x,y,z;
		cin>>x>>y>>z;
		if(x==y)continue;
		for(int i=0;i<=k;i++)
		{
			G[change(x,i)].emplace_back(pii{change(y,i),z});
			G[change(y,i)].emplace_back(pii{change(z,i),z});
		}
		for(int i=0;i<k;i++)
		{
			G[change(x,i)].emplace_back(pii{change(y,i+1),0});
			G[change(y,i)].emplace_back(pii{change(x,i+1),0});
		}
	}
	Dijkstra(0);
	int ans=INT_MAX;
	for(int i=0;i<=k;i++)ans=min(ans,dis[change(n-1,i)]);
	cout<<ans;
	return 0;
}