#pragma GCC target("avx") #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") #include<bits/stdc++.h> // #include<ext/pb_ds/assoc_container.hpp> // #include<ext/pb_ds/tree_policy.hpp> // #include<ext/pb_ds/tag_and_trait.hpp> // using namespace __gnu_pbds; // #include<boost/multiprecision/cpp_int.hpp> // namespace multiprecisioninteger = boost::multiprecision; // using cint=multiprecisioninteger::cpp_int; using namespace std; using ll=long long; using datas=pair<ll,ll>; using ddatas=pair<long double,long double>; using tdata=pair<ll,datas>; using vec=vector<ll>; using mat=vector<vec>; using pvec=vector<datas>; using pmat=vector<pvec>; // using llset=tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>; #define For(i,a,b) for(i=a;i<(ll)b;++i) #define bFor(i,b,a) for(i=b,--i;i>=(ll)a;--i) #define rep(i,N) For(i,0,N) #define rep1(i,N) For(i,1,N) #define brep(i,N) bFor(i,N,0) #define brep1(i,N) bFor(i,N,1) #define all(v) (v).begin(),(v).end() #define allr(v) (v).rbegin(),(v).rend() #define vsort(v) sort(all(v)) #define vrsort(v) sort(allr(v)) #define uniq(v) vsort(v);(v).erase(unique(all(v)),(v).end()) #define endl "\n" #define popcount __builtin_popcountll #define eb emplace_back #define print(x) cout<<x<<endl #define printyes print("Yes") #define printno print("No") #define printYES print("YES") #define printNO print("NO") #define output(v) do{bool f=0;for(auto outi:v){cout<<(f?" ":"")<<outi;f=1;}cout<<endl;}while(0) #define matoutput(v) do{for(auto outimat:v)output(outimat);}while(0) constexpr ll mod=1000000007; // constexpr ll mod=998244353; constexpr ll inf=1LL<<60; constexpr long double eps=1e-9; const long double PI=acosl(-1); template<class T,class E> ostream& operator<<(ostream& os,const pair<T,E>& p){return os<<"("<<p.first<<","<<p.second<<")";} template<class T> ostream& operator<<(ostream& os,const vector<T>& v){ os<<"{";bool f=false; for(auto& x:v){if(f)os<<",";os<<x;f=true;} os<<"}"; return os; } template<class T> ostream& operator<<(ostream& os,const set<T>& v){ os<<"{";bool f=false; for(auto& x:v){if(f)os<<",";os<<x;f=true;} os<<"}"; return os; } template<class T> ostream& operator<<(ostream& os,const multiset<T>& v){ os<<"{";bool f=false; for(auto& x:v){if(f)os<<",";os<<x;f=true;} os<<"}"; return os; } template<class T,class E> ostream& operator<<(ostream& os,const map<T,E>& v){ os<<"{";bool f=false; for(auto& x:v){if(f)os<<",";os<<x;f=true;} os<<"}"; return os; } template<class T> inline bool chmax(T& a,const T b){bool x=a<b;if(x)a=b;return x;} template<class T> inline bool chmin(T& a,const T b){bool x=a>b;if(x)a=b;return x;} #ifdef DEBUG void debugg(){cout<<endl;} template<class T,class... Args>void debugg(const T& x,const Args&... args){cout<<" "<<x;debugg(args...);} #define debug(...) cout<<__LINE__<<" ["<<#__VA_ARGS__<<"]:",debugg(__VA_ARGS__) #else #define debug(...) (void(0)) #endif inline void startupcpp(void) noexcept{ cin.tie(0); ios::sync_with_stdio(false); cout<<fixed<<setprecision(15); } ll modinv(ll a,const ll m=mod) noexcept{ ll b=m,u=1,v=0,t; while(b){ t=a/b; a-=t*b; swap(a,b); u-=t*v; swap(u,v); } return (u+m)%m; } ll moddevide(const ll a,const ll b) noexcept{return (a*modinv(b))%mod;} vec modncrlistp,modncrlistm; ll modncr(const ll n,const ll r) noexcept{ if(n<r)return 0; ll i,size=modncrlistp.size(); if(size<=n){ modncrlistp.resize(n+1); modncrlistm.resize(n+1); if(!size){ modncrlistp[0]=modncrlistm[0]=1; size++; } For(i,size,n+1)modncrlistp[i]=modncrlistp[i-1]*i%mod; modncrlistm[n]=modinv(modncrlistp[n]); for(i=n;i>size;--i)modncrlistm[i-1]=modncrlistm[i]*i%mod; } return modncrlistp[n]*modncrlistm[r]%mod*modncrlistm[n-r]%mod; } ll modpow(ll a,ll n,const ll m=mod){ if(n<0)return 0; ll res=1; while(n>0){ if(n&1)res=res*a%m; a=a*a%m; n>>=1; } return res; } constexpr ll gcd(const ll a,const ll b) noexcept{return (!b)?abs(a):(a%b==0)?abs(b):gcd(b,a%b);} constexpr ll lcm(const ll a,const ll b) noexcept{return a/gcd(a,b)*b;} int val[50000001],cnt[50000001]; ll ans; int main(){ startupcpp(); int N; cin>>N; for(int i=1;i<=N;++i)val[i]=i; for(int i=2;i*i<=N;++i){ int t=i*i; for(int j=1;j*t<=N;j++)val[j*t]=j; } for(int i=1;i<=N;++i)cnt[val[i]]++; for(int i=1;i<=N;++i){ // debug(i,cnt[i]); ans+=ll(cnt[i])*(cnt[i]); } print(ans); // } }