#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxm=50010,maxn=10010;
struct edge{int v,w,from;}e[maxm*3];
int first[maxn],X,n,m,k,q[10010],tot=0;
long long d[2][maxn];
bool vis[maxn];
void insert(int u,int v,int w)
{tot++;e[tot].v=v;e[tot].w=w;e[tot].from=first[u];first[u]=tot;}
void spfa()
{memset(vis,0,n+1);memset(d[X],0x3f,8*(n+1));int head=0,tail=1;q[0]=1;vis[1]=1;d[X][1]=0;while(head!=tail){int x=q[head++];if(head>10000)head=0;for(int i=first[x];i;i=e[i].from)if(d[X][e[i].v]>d[X][x]+e[i].w){int y=e[i].v;d[X][y]=d[X][x]+e[i].w;if(!vis[e[i].v]){if(d[X][y]<d[X][q[head]]){head--;if(head<0)head=10000;q[head]=y;}else{q[tail++]=y;if(tail>10000)tail=0;}vis[e[i].v]=1;}}vis[x]=0;}
//    for(int i=1;i<=n;i++)printf("%d ",d[X][i]);printf("\n");
}
void spfas()
{
//    for(int i=1;i<=n;i++)d[X][i]=d[1-X][i];memset(d[X],0x3f,8*(n+1));int head=0,tail=1;q[0]=1;vis[1]=1;d[X][1]=0;while(head!=tail){int x=q[head++];if(head>10000)head=0;//printf("q %d",x);for(int i=first[x];i;i=e[i].from)if(d[X][e[i].v]>min(d[X][x]+e[i].w,d[1-X][x])){int y=e[i].v;d[X][y]=min(d[X][x]+e[i].w,d[1-X][x]);if(!vis[e[i].v]){if(d[X][y]<d[X][q[head]]){head--;if(head<0)head=10000;q[head]=y;}else{q[tail++]=y;if(tail>10000)tail=0;}vis[e[i].v]=1;}}vis[x]=0;}
//    for(int i=1;i<=n;i++)printf("%d ",d[X][i]);printf("\n");
}
int main()
{scanf("%d%d%d",&n,&m,&k);for(int i=1;i<=m;i++){int u,v,w;scanf("%d%d%d",&u,&v,&w);insert(u,v,w);insert(v,u,w);}X=0;spfa();for(int i=1;i<=k;i++){X=1-X;spfas();}printf("%lld",d[X][n]);return 0;
}

#include<cstdio>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;
const int maxn=100010;
struct edge{int v,w,from;}e[maxn];
struct cyc{int x,k,d;bool operator < (const cyc &a)const{return d>a.d;}
};
priority_queue<cyc>q;
int n,m,first[maxn],tot,d[maxn][30],kind;void insert(int u,int v,int w){tot++;e[tot].v=v;e[tot].w=w;e[tot].from=first[u];first[u]=tot;tot++;e[tot].v=u;e[tot].w=w;e[tot].from=first[v];first[v]=tot;
}
int dijkstra(){q.push((cyc){1,0,0});memset(d,0x3f,sizeof(d));d[1][0]=0;while(!q.empty()){cyc x=q.top();q.pop();if(x.d!=d[x.x][x.k])continue;if(x.x==n)return x.d;for(int i=first[x.x];i;i=e[i].from){if(d[e[i].v][x.k]>d[x.x][x.k]+e[i].w){d[e[i].v][x.k]=d[x.x][x.k]+e[i].w;q.push((cyc){e[i].v,x.k,d[e[i].v][x.k]});}if(x.k<kind&&d[e[i].v][x.k+1]>d[x.x][x.k]){d[e[i].v][x.k+1]=d[x.x][x.k];q.push((cyc){e[i].v,x.k+1,d[e[i].v][x.k+1]});}}}return 0;
}
int main(){scanf("%d%d%d",&n,&m,&kind);int u,v,w;for(int i=1;i<=m;i++){scanf("%d%d%d",&u,&v,&w);insert(u,v,w);}printf("%d",dijkstra());return 0;
}