// #pragma region header #include using namespace std; // #include // using namespace atcoder; // clang-format off /* alias */ using ull = unsigned long long; using ll = long long; using pii = pair; using pll = pair; using vi = vector; using vll = vector; using vd = vector; using vs = vector; using vb = vector; using vpii = vector>; using vpll = vector>; using vvi = vector>; using vvll = vector>; using vvd = vector>; using vvs = vector>; using vvb = vector>; template using min_priority_queue = priority_queue, greater>; /* define */ #define MOD 998244353 // #define MOD 1000000007 #define INF (1LL << 60) #define inf (1 << 28) #define elif else if #define pb push_back #define pf push_front #define fi first #define se second #define all(obj) (obj).begin(), (obj).end() #define YESNO(bool) cout << (bool ? "YES\n" : "NO\n") #define YesNo(bool) cout << (bool ? "Yes\n" : "No\n") #define yesno(bool) cout << (bool ? "yes\n" : "no\n") template bool chmax(T &a, const T &b) {if(a bool chmin(T &a, const T &b) {if(b= 0; i--) #define rrepd(i, n) for(ll i = (n); i >= 1; i--) #define fore(i, a) for(auto &i: a) /* vector */ template T vmax(vector &array){ T ret = array[0]; for(T a: array) chmax(ret, a); return ret; } template T vmin(vector &array){ T ret = array[0]; for(T a: array) chmin(ret, a); return ret; } template T sum(vector &array){ T ret = 0; for(T a:array) ret += a; return ret; } template void list_set(vector &array){ sort(all(array)); array.erase(unique(all(array)),array.end()); } template T bisect_left(vector &array, T key){ return lower_bound(all(array),key) - array.begin(); } template T bisect_right(vector &array, T key){ return upper_bound(all(array),key) - array.begin(); } /* string */ ll string_to_ll(string n){ ll ret = 0, k = 1; while(n.length() > 0){ ret += k * (n.back() - '0'); n.pop_back(); k *= 10; } return ret; } string ll_to_string(ll n){ string ret = ""; while(n > 0){ ret.pb((n % 10) + '0'); n /= 10; } reverse(all(ret)); return ret; } struct popopo{ popopo(){ cin.tie(0); ios::sync_with_stdio(0); cout << fixed << setprecision(15); }; } popopoppo; // n = 1,...,N に対して、n % A < B を満たすものの数 ll Count_of_n_mod_A_less_than_B(ll N, ll A, ll B){ return N / A * min(A, B) + min(N % A, B - 1); } /* IN/OUT */ int scan() { return getchar(); } void scan(int &a) { cin >> a; } void scan(long long &a) { cin >> a; } void scan(char &a) { cin >> a; } void scan(double &a) { cin >> a; } void scan(string &a) { cin >> a; } template void scan(pair &p) { scan(p.first), scan(p.second); } template void scan(vector &); template void scan(vector &a) { for(auto &i : a) scan(i); } void IN(){} template void IN(Head& head, Tail &...tail){ scan(head); IN(tail...); } #define INT(...) int __VA_ARGS__; IN(__VA_ARGS__) #define LL(...) ll __VA_ARGS__; IN(__VA_ARGS__) #define STR(...) string __VA_ARGS__; IN(__VA_ARGS__) #define VEC(type, name, size) vector name(size); IN(name) #define VECS(type, name, size) vector name(size + 1); for(int i = 1; i <= size; i++) scan(name[i]) void OUT(){ cout << "\n"; } template void output(T a){ cout << a; } template void output(vector v){ for(int i = 0; i < v.size(); i++) cout << v[i] << (i == v.size() - 1 ? "" : " "); } template void OUT(const Head &head, const Tail &...tail) { output(head); if(sizeof...(tail)) cout << " "; OUT(tail...); } void FLASH(){ cout << endl; } template void FLASH(const Head &head, const Tail &...tail) { output(head); if(sizeof...(tail)) cout << " "; FLASH(tail...); } // clang-format on // #pragma endregion header int main() { LL(N); ll ans = 0; for (ll x = 0; x < 10; x++) { for (ll y = 0; y < 10; y++) { if (x == y) continue; auto check = [&N](ll a, ll b, ll p) -> bool { return N * (a * p + b) > p * p - 1; }; // max(x, y) + 1 <= かつ <= 10^9 のうちで、行ける最大の p は? if (!check(x, y, max(max(x, y) + 1, 2LL))) continue; ll ok = max(max(x, y) + 1, 2LL), ng = 1e9 + 1; while (abs(ok - ng) > 1) { ll mid = (ok + ng) / 2; if (check(x, y, mid)) { ok = mid; } else { ng = mid; } } ans += ok - max(max(x, y) + 1, 2LL) + 1; } } OUT(ans); }