#include <bits/stdc++.h> using namespace std; using Int = long long; const char newl = '\n'; template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;} template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;} template<typename T> void drop(const T &x){cout<<x<<endl;exit(0);} template<typename T=Int> vector<T> read(size_t n){ vector<T> ts(n); for(size_t i=0;i<n;i++) cin>>ts[i]; return ts; } //INSERT ABOVE HERE const Int MAX = 5e7 + 100; signed dp[MAX]; signed cnt[MAX]; signed main(){ cin.tie(0); ios::sync_with_stdio(0); Int n; cin>>n; for(Int i=1;i<=n;i++) dp[i]=i; for(Int i=2;i*i<=n;i++){ Int s=i*i; for(Int j=s;j<=n;j+=s) while(dp[j]%s==0) dp[j]/=s; } Int ans=0; for(Int i=1;i<=n;i++) cnt[dp[i]]++; for(Int i=1;i<=n;i++) ans+=1LL*cnt[i]*cnt[i]; cout<<ans<<newl; return 0; }