#include using namespace std; #define FOR(i,m,n) for(int i=(m);i<(n);++i) #define REP(i,n) FOR(i,0,n) using ll = long long; constexpr int INF = 0x3f3f3f3f; constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL; constexpr double EPS = 1e-8; constexpr int MOD = 998244353; // constexpr int MOD = 1000000007; constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1}; constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1}; constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1}; template inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; } template inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; } struct IOSetup { IOSetup() { std::cin.tie(nullptr); std::ios_base::sync_with_stdio(false); std::cout << fixed << setprecision(20); } } iosetup; template std::vector z_algorithm(const T &s) { const int n = s.size(); std::vector res(n, 0); for (int i = 1, j = 0; i < n; ++i) { if (i + res[i - j] < j + res[j]) { res[i] = res[i - j]; } else { res[i] = std::max(j + res[j] - i, 0); while (i + res[i] < n && s[i + res[i]] == s[res[i]]) ++res[i]; j = i; } } res[0] = n; return res; } void solve() { int n; string s; cin >> n >> s; const vector z = z_algorithm(s); int ans = 0; FOR(i, 1, n) { const int cp = min({z[i], i, n - i}); if (cp == i && cp == n - i) { // U = V } else if (cp == i) { ++ans; } else if (cp == n - i) { // U > V } else { ans += s[cp] < s[i + cp]; } } cout << ans << '\n'; } int main() { int t; cin >> t; while (t--) solve(); return 0; }