def arithmetic_right_shift(S, K):
    n = len(S)
    if K >= n:
        return S[0] * n
    for _ in range(K):
        S = S[0] + S[:-1]
    return S

T = int(input())
for _ in range(T):
    K = int(input())
    S = input().strip()
    print(arithmetic_right_shift(S, K))