#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

bool f;
int t, n, cur, sz;
unsigned long long a, b, tmp, stp;
string str, r, s, ans;
char ch;

void fib() {
	tmp = a + b;
	a = b;
	b = tmp;
}

int main() {
	cin >> t;
	while (t-- && cin >> n) {
		cin.ignore();
		getline(cin, str);

		a = 0, b = 1;	cur = -1;
		ans = "";
		sz = str.size() - 1;
		f = true;

		s = string(str.begin() + 1, str.end());
		r = str;
		reverse(r.begin(), r.end());
		r = string(r.begin() + 1, r.end());

		while (n) {
			fib();
			stp = b - a;
			if (!stp)	stp = 1;
			cur += stp;
			if (cur >= (f ? sz + 1 : sz)) {
				if (f) {
					f = false;
					cur--;
				}
				tmp = cur / sz;
				cur %= sz;
				if (tmp % 2)
					ch = r[cur];
				else
					ch = s[cur];
			}
			if (ch != '-') {
				ans += ch;
				n--;
			}
			else
				a = 0, b = 1;
		}
		cout << ans << endl;
	}
	return 0;
}