#include "bits/stdc++.h"
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
using namespace std;
using ll = long long int;
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
 
struct input_checker {
	string buffer;
	int pos;
 
	const string all = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
	const string number = "0123456789";
	const string upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	const string lower = "abcdefghijklmnopqrstuvwxyz";
 
	input_checker() {
		pos = 0;
		while (true) {
			int c = cin.get();
			if (c == -1) {
				break;
			}
			buffer.push_back((char) c);
		}
	}
 
	int nextDelimiter() {
		int now = pos;
		while (now < (int) buffer.size() && buffer[now] != ' ' && buffer[now] != '\n') {
			now++;
		}
		return now;
	}
 
	string readOne() {
		assert(pos < (int) buffer.size());
		int nxt = nextDelimiter();
		string res;
		while (pos < nxt) {
			res += buffer[pos];
			pos++;
		}
		// cerr << res << endl;
		return res;
	}
 
	string readString(int minl, int maxl, const string &pattern = "") {
		assert(minl <= maxl);
		string res = readOne();
		assert(minl <= (int) res.size());
		assert((int) res.size() <= maxl);
		for (int i = 0; i < (int) res.size(); i++) {
			assert(pattern.empty() || pattern.find(res[i]) != string::npos);
		}
		return res;
	}
 
	int readInt(int minv, int maxv) {
		assert(minv <= maxv);
		int res = stoi(readOne());
		assert(minv <= res);
		assert(res <= maxv);
		return res;
	}
 
	long long readLong(long long minv, long long maxv) {
		assert(minv <= maxv);
		long long res = stoll(readOne());
		assert(minv <= res);
		assert(res <= maxv);
		return res;
	}
 
	void readSpace() {
		assert((int) buffer.size() > pos);
		assert(buffer[pos] == ' ');
		pos++;
	}
 
	void readEoln() {
		assert((int) buffer.size() > pos);
		assert(buffer[pos] == '\n');
		pos++;
	}
 
	void readEof() {
		assert((int) buffer.size() == pos);
	}
};
 
int main()
{
	ios::sync_with_stdio(false); cin.tie(0);
 
	input_checker inp;
 
	int sumn = 0, minn = 100'001, maxn = 0;
	int summ = 0, minm = 100'001, maxm = 0;
	int t = inp.readInt(1, 100'000);
	inp.readEoln();
 
	while (t--) {
		int n = inp.readInt(1, 100'000); inp.readSpace();
		int m = inp.readInt(1, 100'000); inp.readEoln();
		sumn += n; maxn = max(maxn, n); minn = min(minn, n);
		summ += m; maxm = max(maxm, m); minm = min(minm, m);
 
		string text = inp.readString(n, n); inp.readEoln();
		string pat = inp.readString(m, m); inp.readEoln();
 
		int ptr = 0;
		for (auto &c : text) {
			if (ptr < m and pat[ptr] == c) ++ptr;
			if (ptr == m) break;
			if (c != '?') continue;
			for (int i = 0; i < 5; ++i) {
				if (pat[ptr] == 'a'+i) continue;
				c = 'a' + i;
				break;
			}
		}
		if (ptr == m) cout << "-1\n";
		else cout << text << '\n';
	}
	inp.readEof();
	assert(sumn <= 300'000);
	assert(summ <= 300'000);
 
	cerr << "Sum N, M: " << sumn << ' ' << summ << '\n';
	cerr << "Maximum N, M: " << maxn << ' ' << maxm << '\n';
	cerr << "Minimum N, M: " << minn << ' ' << minm << '\n';
}