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()
    Z = z_algo(S)
    ans = 0
    for i in range(1, N):
        if i < Z[i]:
            ans += 1
            continue
        if i == Z[i] and i+Z[i] < N:
            ans += 1
            continue
        if i == Z[i]:
            continue
        if i+Z[i] == N:
            continue
        if S[Z[i]] < S[i+Z[i]]:
            ans += 1
    print(ans)