def z_algo(S):
    N = len(S)
    A = [0] * N
    i = 1;
    j = 0
    A[0] = l = len(S)
    while i < l:
        while i + j < l and S[j] == S[i + j]:
            j += 1
        if not j:
            i += 1
            continue
        A[i] = j
        k = 1
        while l - i > k < j - A[k]:
            A[i + k] = A[k]
            k += 1
        i += k;
        j -= k
    return A

T = int(input())
for _ in range(T):
    N = int(input())
    S = input()
    A = z_algo(S)
    ans = 0
    for i in range(1, N):
        j = A[i]
        if i < j:
            ans += 1
        elif i + j < N:
            if i == j:
                ans += 1
            elif S[j] < S[i + j]:
                ans += 1
    print(ans)