/*And I thought my jokes were bad*/
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define dbg puts("Viva la vida");
#define CHECK(x) cout << (#x) << " is " << (x) << endl;
#define nl puts("");
#define mp make_pair
#define IN(x) scanf("%d",&x);
#define INL(x) scanf("%lld",&x);
#define OUT(x) printf("%d",x);
#define OUTL(x) printf("%lld",x);
#define MAX 200005
#define MOD 1000000009
#define INF (1 << 31)
#define CASE(x,y) printf("Case %d: %d\n",++x,y);
#define FASTIO ios::sync_with_stdio(false);cin.tie(0);
#define PI acos(-1.0)
#define EPS 1e-19
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
// #define int ll
/*
	When I get older
	I will be stronger
	they'll call me freedom
	just like a waving flag
*/
int arr[MAX],n;
int dp[505][505][505];
int sol(int i,int mx,int x)
{
	if(i==n)
		return 0;

	if(arr[i]<mx)
	{
		return 505;
	}
	int &ret=dp[i][mx][x];
	if(~ret) return ret;
	if(arr[i]<=x||x<mx)
		return ret=sol(i+1,arr[i],x);
	else
		return ret=min(sol(i+1,arr[i],x),1+sol(i+1,x,arr[i]));
}


void solve()
{
	int i,j,k,l,r,m,a,b,c,d,x,y,z,t,p;
	cin>>n>>x;
	for(i=0;i<n;i++)
		cin>>arr[i];
	for(i=0;i<=n;i++)
		for(j=0;j<=500;j++)
			for(k=0;k<=500;k++)
				dp[i][j][k]=-1;
	int ans=sol(0,0,x);
	if(ans>=505)
		ans=-1;
	cout<<ans<<endl;


}
int32_t main()
{
	FASTIO
    int t=1;
    cin>>t;
    while(t--) solve();
    return 0;
}