#include<queue>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define MAXN 1100
#define MAXM MAXN*MAXN
#define INF 0x7fffffff
using namespace std;
queue<int>que;
int t,n,d,tot,kase;
int dis[MAXN],vis[MAXN],num[MAXN],id;
int to[MAXM],net[MAXM],cap[MAXM],head[MAXN];
struct House{ int high;int no; }arr[MAXN];
int cmp(House a,House b){ return a.high<b.high; }
void add(int u,int v,int w){ to[++tot]=v;cap[tot]=w;net[tot]=head[u];head[u]=tot; }
int spfa(int s,int t,int n){
    memset(num,0,sizeof(num));
    memset(vis,0,sizeof(vis));
    memset(dis,0x7f,sizeof(dis));
    while(!que.empty())    que.pop();
    dis[s]=0;vis[s]=1;que.push(s);
    while(!que.empty()){
        int now=que.front();
        que.pop();
        vis[now]=0;num[now]++;
        if(num[now]>n) return -1;
        for(int i=head[now];i;i=net[i]){
            if(dis[to[i]]>dis[now]+cap[i]){
                dis[to[i]]=dis[now]+cap[i];
                if(!vis[to[i]]){
                    vis[to[i]]=1;
                    que.push(to[i]);
                }
            }
        }
    }
    return dis[t];
}
int main(){
    scanf("%d",&t);
    while(t--){
        memset(head,0,sizeof(head));
        scanf("%d%d",&n,&d);tot=0;
        for (int i=1;i<=n;i++){
            scanf("%d",&arr[i].high);
            arr[i].no=i;
            if(i!=n)    add(i+1,i,-1);
        }
        sort(arr+1,arr+n+1,cmp);
        for(int i=1;i<n;i++){
            int u=arr[i].no;
            int v=arr[i+1].no;
            if(u>v) swap(u,v);
            add(u,v,d);
        }
        int u=arr[1].no,v=arr[n].no;
        if(u>v)    swap(u,v);
        printf("Case %d: %d\n",++kase,spfa(u,v,n));
    }
}