DSA02021.cpp

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <cstring>
#include <algorithm>
#include <queue>
#include <map>
#include <unordered_map>
#include <set>
#include <stack>
#include <cmath>
#include <iomanip>
#include <climits>
#include <cstdlib>
#include <numeric>
#include <unordered_set>
using namespace std;

#define ll long long
// MAX (long long) 1000000000000000000
//#define M 100 + 5
#define N 1003

#define MOD (ll) 1000000007
#define ld long double
#define sz size()
#define FOR(i, a, b) for(int i = a; i <= b; i++)
#define FORD(i, a, b) for (int i = a; i >= b; i--)
#define faster() ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
#define zero(n) setw(n) << setfill('0')
#define stp(n) fixed << setprecision(n)

int main() {
	int t;
	cin >> t;

	while (t--) {
		string s;
		ll n;
		cin >> s >> n;

		ll x = s.size();
		while (x < n) x <<= 1;

		while (x > s.size()) {
			ll tmp = x >> 1;
			if (n > tmp) {
				n -= tmp;
				n--;
				if (n == 0) n = tmp;
			}
			x >>= 1;
		}
		cout << s[n - 1] << endl;
	}

	return 0;
}