/* Problem URL: https://codeforces.com/problemset/problem/2111/E */

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t;
    cin >> t;
    while (t--) {
        int n, m;
        cin >> n >> m;

        string a;
        cin >> a;

        repv(i, a) {
            i -= 'a';
        }

        vvi ops(3, vi(3));

        while (m--) {
            char b, c;
            cin >> b >> c;
            b -= 'a';
            c -= 'a';

            ops[b][c]++;
        }

        repv(i, a) {
            if (i == 0) {
                continue;
            }

            if (i == 1 && ops[1][0]) {
                ops[1][0]--;
                i = 0;
                continue;
            }

            if (i == 1 && ops[1][2] && ops[2][0]) {
                ops[1][2]--;
                ops[2][0]--;
                i = 0;
                continue;
            }

            if (i == 2 && ops[2][0]) {
                ops[2][0]--;
                i = 0;
                continue;
            }
            
            if (i == 2 && ops[2][1] && ops[1][0]) {
                ops[2][1]--;
                ops[1][0]--;
                i = 0;
                continue;
            }

            if (i == 2 && ops[2][1]) {
                ops[2][1]--;
                i = 1;
            }
        }

        repv(i, a) {
            cout << (char)(i + 'a');
        }
        cout << '\n';
    }
}