include

include

include

using namespace std;

int main() {

int n, q, min, flage, m, b, c;
int  a[1010];
scanf("%d%d", &n, &q);
for (int i = 0; i < n; i++)
	scanf("%d", &a[i]);
while (q--) {
	scanf("%d%d", &m, &b);
	c = pow(10, m);
	min = numeric_limits<int>::max();
	flage = 0;
	for (int i = 0; i < n; i++) {
		int d = a[i] % c;
		if (d == b) {
			flage = 1;
			if (a[i] < min) {
				min = a[i];
			}
		}
	}
	if (flage)
		cout << min << endl;
	else
		cout << "-1" << endl;
}
return 0;

}