#include<bits/stdc++.h>
#define ll long long
#define vi vector<int>
#define vll vector<ll>
#define eb emplace_back
#define pb push_back
#define all(v) v.begin(),v.end()
#define sz(v) ((int)v.size())
#define pii pair<int,int>
#define pll pair<ll,ll>
#define fi first
#define se second
#define umap unordered_map
using namespace std;
namespace qiqi {
	const int inf = 1e9,P[2] = {(int)1e9+7,(int)1e9+9},B = 27;
	struct SH {
		int v[2];
		SH():v{0,0} {}
		SH(int a,int b):v{a,b} {}
		SH friend operator + (SH x,int k) {
			SH y; for (int i = 0; i < 2; i++) {
				y.v[i] = (1ll*B*x.v[i]+k+1)%P[i];
			}
			return y;
		}
		bool friend operator == (SH x,SH y) {
			return x.v[0] == y.v[0] && x.v[1] == y.v[1];
		}
		bool friend operator < (SH x,SH y) {
			return pair(x.v[0],x.v[1]) < pair(y.v[0],y.v[1]);
		}
	};
	void main() {
		int n,m;
		cin >> n >> m;
		vi c(m,inf); c[0] = 0;
		vector<vector<SH>> a(n);
		for (int i = 0; i < n; i++) {
			string s; cin >> s;
			int k = sz(s);
			c[k%m] = min(c[k%m],k/m+1);
			a[i].assign(k+1,SH());
			for (int j = 0; j < k; j++) {
				a[i][j+1] = a[i][j]+(s[j]-'a');
			}
		}
		for (int i = 1; i < m; i++) {
			int g = __gcd(i,m);
			for (int j = 0; j < g; j++) {
				for (int k = 0,x = i,y = (x+i)%m; k <= 2*m/g; k++,x = y,y = (y+i)%m) {
					c[y] = min(c[y],c[x]+c[i]+(y < x));
				}
			}
		}
		map<SH,int> mp;
		for (int i = 0; i < n; i++) {
			int x = sz(a[i]);
			for (int j = 1; j < x; j++) {
				int y = c[(m-(x-j-1)%m)%m]+(x-j-1+m-1)/m+1;
				if (y != inf) {
					if (mp.find(a[i][j]) == mp.end()) {
						mp[a[i][j]] = y;
					}
					else {
						mp[a[i][j]] = min(mp[a[i][j]],y);
					}
				}
			}
		}
		string s; cin >> s;
		n = sz(s);
		vi f(n+1,inf); f[0] = 0;
		for (int i = 0; i < n; i++) {
			SH x;
			for (int j = i; j < n; j++) {
				x = x+(s[j]-'a');
				auto it = mp.find(x);
				if (it != mp.end()) {
					f[j+1] = min(f[j+1],f[i]+it->se);
				}
			}
		}
		if (f[n] == inf) {
			cout << "-1\n";
			return;
		}
		cout << f[n] << '\n';
	}
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	int T; cin >> T;
	while (T--) qiqi::main();
	return 0;
}