n, q = map(int, input().split())
a = [input() for i in range(n)]
b1 = []
b2 = []
for i in range(q):
    b10, b20 = input().split()
    b1.append(b10)
    b2.append(b20)
a.sort(key=lambda x: int(x))
for j in range(q):
    for k in range(n):
        if b2[j] == a[k][-int(b1[j]):]:
            print(a[k])
            n -= 1
            break
    else:
        print(-1)