import sys
input = sys.stdin.readline

def Z_algorithm(s):
    n = len(s)
    A = [n] + [0] * (n-1)
    i, j = 1, 0
    while i < n:
        while i + j < n and s[j] == s[i+j]:
            j += 1
        A[i] = j
        if j == 0:
            i += 1
            continue
        k = 1
        while i + k < n and k + A[k] < j:
            A[i+k] = A[k]
            k += 1
        i += k
        j -= k
    return A

T = int(input())
for _ in range(T):
    N = int(input())
    S = list(input().rstrip())
    S = [ord(s) - ord("a") for s in S]
    L = Z_algorithm(S)
    ans = 0
    for i in range(1, N):
        L[i] = min(i, L[i])
        if i == L[i] and 2 * i < N:
            ans += 1
        else:
            if i + L[i] <= N - 1:
                if S[L[i]] < S[i + L[i]]:
                    ans += 1
    print(ans)