def f1(s):
    d = {1 + i: int(x) for i, x in enumerate(s) if x != "0"}
    return int("".join([f"{k}" * v for k, v in d.items()]))


def f2(a, m):
    x = int(f"{a}{m}")
    x -= x % m
    return x


for _ in range(int(input())):
    m = int(input())
    a = f1(input().split())
    print(f2(a, m))