/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
public class Main
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		while(t-- > 0){
			int n = sc.nextInt();
			int m = sc.nextInt();
			String a= sc.next();
			String b = sc.next();
 
			int ans=0,p1=0,p2=0;
			while(p1<n && p2<m){
				if(a.charAt(p1) == b.charAt(p2)){
					p1++;
					p2++;
					ans++;
				}else{
					p2++;
				}
			}
			System.out.println(ans);
		}
	}
}

LyogcGFja2FnZSB3aGF0ZXZlcjsgLy8gZG9uJ3QgcGxhY2UgcGFja2FnZSBuYW1lISAqLwoKaW1wb3J0IGphdmEudXRpbC4qOwppbXBvcnQgamF2YS5sYW5nLio7CmltcG9ydCBqYXZhLmlvLio7CgovKiBOYW1lIG9mIHRoZSBjbGFzcyBoYXMgdG8gYmUgIk1haW4iIG9ubHkgaWYgdGhlIGNsYXNzIGlzIHB1YmxpYy4gKi8KcHVibGljIGNsYXNzIE1haW4KewoJcHVibGljIHN0YXRpYyB2b2lkIG1haW4gKFN0cmluZ1tdIGFyZ3MpIHRocm93cyBqYXZhLmxhbmcuRXhjZXB0aW9uCgl7CgkJU2Nhbm5lciBzYyA9IG5ldyBTY2FubmVyKFN5c3RlbS5pbik7CgkJaW50IHQgPSBzYy5uZXh0SW50KCk7CgkJd2hpbGUodC0tID4gMCl7CgkJCWludCBuID0gc2MubmV4dEludCgpOwoJCQlpbnQgbSA9IHNjLm5leHRJbnQoKTsKCQkJU3RyaW5nIGE9IHNjLm5leHQoKTsKCQkJU3RyaW5nIGIgPSBzYy5uZXh0KCk7CgkJCgkJCWludCBhbnM9MCxwMT0wLHAyPTA7CgkJCXdoaWxlKHAxPG4gJiYgcDI8bSl7CgkJCQlpZihhLmNoYXJBdChwMSkgPT0gYi5jaGFyQXQocDIpKXsKCQkJCQlwMSsrOwoJCQkJCXAyKys7CgkJCQkJYW5zKys7CgkJCQl9ZWxzZXsKCQkJCQlwMisrOwoJCQkJfQoJCQl9CgkJCVN5c3RlbS5vdXQucHJpbnRsbihhbnMpOwoJCX0KCX0KfQ==

Ngo1IDQKMTAwMTEKMTExMAozIDMKMTAwCjExMAoxIDMKMQoxMTEKNCA0CjEwMTEKMTExMQozIDUKMTAwCjExMDEwCjMgMQoxMDAKMAo=

6
5 4
10011
1110
3 3
100
110
1 3
1
111
4 4
1011
1111
3 5
100
11010
3 1
100
0