#line 1 "library-cpp/other/template.hpp" // clang-format off #include using namespace std; using uint = unsigned int; using ll = long long; using ull = unsigned long long; using ld = long double; using pii = pair; using pll = pair; template using maxheap = priority_queue; template using minheap = priority_queue, greater>; template using vec = vector; template using vvec = vector>; #define OVERLOAD_REP(_1, _2, _3, name, ...) name #define REP0(n) for (auto minato = decay_t{}; minato < (n); ++minato) #define REP1(i, n) for (auto i = decay_t{}; (i) < (n); (i)++) #define REP2(i, l, r) for (auto i = (l); (i) < (r); (i)++) #define rep(...) OVERLOAD_REP(__VA_ARGS__, REP2, REP1, REP0)(__VA_ARGS__) #define OVERLOAD_RREP(_1, _2, _3, name, ...) name #define RREP1(i, n) for (auto i = (n) - 1; (i) >= decay_t{}; (i)--) #define RREP2(i, l, r) for (auto i = (r) - 1; (i) >= (l); (i)--) #define rrep(...) OVERLOAD_RREP(__VA_ARGS__, RREP2, RREP1)(__VA_ARGS__) #define all(x) begin(x), end(x) template int SZ(const Container& v) { return int(v.size()); } template void UNIQUE(vector& v) { v.erase(unique(v.begin(), v.end()), v.end()); } template T MAX(const vector& v) { return *max_element(v.begin(), v.end()); } template T MIN(const vector& v) { return *min_element(v.begin(), v.end()); } template T SUM(const vector& v) { return *accumulate(v.begin(), v.end(), T(0)); } template bool chmax(T1& a, T2 b) { if (a < b) { a = b; return true; } return false; } template bool chmin(T1& a, T2 b) { if (a > b) { a = b; return true; } return false; } int topbit(ull x) { return x == 0 ? -1 : 63 - __builtin_clzll(x); } int botbit(ull x) { return x == 0 ? 64 : __builtin_ctzll(x); } int popcount(ull x) { return __builtin_popcountll(x); } int kthbit(ull x, int k) { return (x >> k) & 1; } constexpr long long TEN(int x) { return x == 0 ? 1 : TEN(x - 1) * 10; } template void rearrange(const vector& id) {} template void rearrange_exec(const vector& id, vector& v) { vector w(v.size()); for (size_t i = 0; i < id.size(); i++) { w[i] = v[id[i]]; } v.swap(w); } template void rearrange(const vector& id, Head& a, Tail& ...tail) { rearrange_exec(id, a); rearrange(id, tail...); } constexpr char ln = '\n'; const string YESNO[2] = {"NO", "YES"}; const string YesNo[2] = {"No", "Yes"}; void YES(bool t = true) { cout << YESNO[t] << "\n"; } void Yes(bool t = true) { cout << YesNo[t] << "\n"; } template void drop(T x) { cout << x << "\n"; exit(0); } #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 CHR(...) \ char __VA_ARGS__; \ IN(__VA_ARGS__) #define LDB(...) \ long double __VA_ARGS__; \ IN(__VA_ARGS__) #define VEC(type, name, size) \ vector name(size); \ IN(name) #define VEC2(type, name1, name2, size) \ vector name1(size), name2(size); \ for (int i = 0; i < size; i++) IN(name1[i], name2[i]) #define VEC3(type, name1, name2, name3, size) \ vector name1(size), name2(size), name3(size); \ for (int i = 0; i < size; i++) IN(name1[i], name2[i], name3[i]) #define VEC4(type, name1, name2, name3, name4, size) \ vector name1(size), name2(size), name3(size), name4(size); \ for (int i = 0; i < size; i++) IN(name1[i], name2[i], name3[i], name4[i]); #define VV(type, name, N, M) \ vector> name(N, vector(M)); \ IN(name) template void scan(T& a) { cin >> a; } template void scan(vector& a) { for (auto& i : a) scan(i); } void IN() {} template void IN(Head& head, Tail&... tail) { scan(head); IN(tail...); } void print() { cout << "\n"; } template void print(const vector& v) { for (auto it = v.begin(); it != v.end(); ++it) { if (it != v.begin()) { cout << " "; } cout << *it; } print(); } template void print(const T& x, const Args& ... args) { cout << x; if (sizeof...(Args)) cout << " "; print(args...); } #ifdef MINATO_LOCAL template ostream& operator<<(ostream& os, pair p) { return os << "(" << p.first << ", " << p.second << ")"; } template void debug_tuple(ostream& os, TUPLE _) { (void)os; (void)_; } template void debug_tuple(ostream &os, TUPLE t) { os << (N == 0 ? "" : ", ") << get(t); debug_tuple(os, t); } template ostream& operator<<(ostream& os, tuple t) { os << "("; debug_tuple<0, tuple, Args...>(os, t); return os << ")"; } string debug_delim(int& i) { return i++ == 0 ? "" : ", "; } #define debug_embrace(x) { int i = 0; os << "{"; { x } return os << "}"; } template ostream& operator<<(ostream& os, vector v) { debug_embrace( for (T e : v) { os << debug_delim(i) << e; } ) } template ostream& operator<<(ostream& os, array a) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) } template enable_if_t>, ostream>& operator<<(ostream& os, T(&a)[N]) { debug_embrace( for (T e : a) { os << debug_delim(i) << e; } ) } template ostream& operator<<(ostream& os, set s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) } template ostream& operator<<(ostream& os, map mp) { debug_embrace( for (auto e : mp) { os << debug_delim(i) << e; }) } template ostream& operator<<(ostream& os, multiset s) { debug_embrace( for (Key e : s) { os << debug_delim(i) << e; }) } template ostream& operator<<(ostream& os, queue q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.front(); } ) } template ostream& operator<<(ostream& os, deque q) { debug_embrace( for (T e : q) { os << debug_delim(i) << e; } ) } template ostream& operator<<(ostream& os, priority_queue q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) } template ostream& operator<<(ostream& os, priority_queue, greater> q) { debug_embrace( for (; !q.empty(); q.pop()) { os << debug_delim(i) << q.top(); } ) } void debug_out() { cerr << endl; } template void debug_out(const T& x, const Args& ... args) { cerr << " " << x; debug_out(args...); } #define debug(...) cerr << __LINE__ << " : [" << #__VA_ARGS__ << "] =", debug_out(__VA_ARGS__) #else #define debug(...) (void(0)) #endif struct fast_ios { fast_ios() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); cerr << fixed << setprecision(7); }; } fast_ios_; /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // clang-format on #line 2 "A.cpp" void solve() { LL(N); vec table(N + 1); iota(all(table), 0); vec freq(N + 1); rrep(i, 1LL, N + 1) { ll k = i * i; for (ll x = k; x <= N; x += k) { if (table[x] % k == 0) table[x] /= k; } } rep(i, 1, N + 1) freq[table[i]]++; ll ans = 0; rep(i, 1, N + 1) ans += 1LL * freq[i] * freq[i]; print(ans); } int main() { int T = 1; // cin >> T; for (int i = 0; i < T; i++) { solve(); } }