Hackers and Neural Networks（Round 1016）

import java.util.*;

public class F {
    static Scanner sc=new Scanner(System.in);
    static void sv() {
        int n=sc.nextInt(),m=sc.nextInt();
        String s[][]=new String[m+1][n+1];
        int cnt[]=new int[m+1],res=n,ma=0;
        boolean vis[]=new boolean[n+1];
        String ans[]=new String[n+1];
        for (int i=1;i<=n;++i) ans[i]=sc.next();
        for (int i=1;i<=m;++i) {
            for (int j=1;j<=n;++j) {
                s[i][j]=sc.next();
                if (s[i][j].equals(ans[j])) {
                    vis[j]=true;
                    cnt[i]++;
                    ma=Math.max(ma,cnt[i]);
                }
            }
        }
        for (int i=1;i<=n;++i) {
            if (!vis[i]) {
                System.out.println("-1");
                return;
            }
        }
        System.out.println(n+(n-ma)*2);
    }
    public static void main(String[] args) {
        int t=sc.nextInt();
        while (t-->0) sv();
    }
}