#include <iostream>
#include <string>
using namespace std;
 
// 判断删除子串后的s是否等于t
bool canBeMadeEqual(string& s, string& t, int l, int r) {
    string modified = s.substr(0, l) + s.substr(r);  // 删除 s[l, r) 这段子串
    return modified == t;  // 检查是否与 t 相等
}
 
int main() {
    int T;
    cin >> T;
 
    while (T--) {
        int m, n;
        cin >> m >> n;
        string s, t;
        cin >> s >> t;
 
        bool found = false;
        for (int i = 0; i <= m - n; i++) {
            // 尝试删除 s 中的任意一个子串，使得剩余部分与 t 相等
            for (int j = i + n; j <= m; j++) {
                if (canBeMadeEqual(s, t, i, j)) {
                    found = true;
                    break;
                }
            }
            if (found) break;
        }
 
        cout << (found ? "YES" : "NO") << endl;
    }
 
    return 0;
}
 

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