#include <bits/stdc++.h>
using namespace std;
#define int long long
const long double PI = 3.14159265359;
void solve()
{
int n, m;
cin >> n >> m;
string p, q;
cin >> p >> q;
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
if (p[i] == q[j])
{
p[i] = '?', q[j] = '.';
break;
}
}
}
int s = 0, ic = 0, x = 0, total = 0;
for (int i = 0; i < n; i++)
{
if (p[i] == 's')
s++;
if (p[i] == 'i')
ic++;
if (p[i] == 'x')
x++;
if (p[i] != '?')
total++;
}
if (total == 3 && s == 1 && x == 1 && ic == 1 && count(q.begin(), q.end(), '.') == m)
cout << "YES" << '\n';
else
cout << "NO" << '\n';
}
signed main(void)
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
if (fopen("input.txt", "r"))
{
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
}
int t = 1;
cin >> t;
while (t--)
{
solve();
}
return 0;
}
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