include <bits/stdc++.h>

using namespace std;

int main() {

int n, q;
cin >> n >> q;

vector<int> books(n);
for (int i = 0; i < n; ++i) {
	cin >> books[i];
}

sort(books.begin(), books.end());

while (q--) {
	int l, x;
	cin >> l >> x;

	int mod = 1;
	for (int i = 0; i < l; i++) {
		mod *= 10;
	}
	if (x >= mod) {
		cout << -1 << endl;
		continue;
	}

	int res = -1;

// 范围for 等价于 // for (int i = 0; i < books.size(); i++) { // int num = books[i]; // if (num % mod_val == x) { // result = num; // break; // } // }

	for (int num : books) {
		if (num % mod == x) {
			res = num;
			break;
		}
	}

	cout << res << endl;
}

return 0;

}