#include<bits/stdc++.h>

using namespace std;

#define rep(i,n) for (int i = 0; i < n; i++)
#define rep1(i,n) for(int i = 1;i<=(n);i++)
#define rrep(i,n) for(int i = (n)-1;i>=0;i--)
#define rrep1(i, n) for (int i = (n); i > 0; i--)
#define REP(i, a, b) for (int i = a; i < b; i++)
#define ALL(a) a.begin(),a.end()
#define elif else if
#define foreach(elem,a) for (auto elem : a)
#define list vector

template<class T> ostream& operator << (ostream &s, vector<T> &P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }

template <class T>bool chmax(T &a, T b){if (a < b){a = b;return true;}return false;}
template <class T>bool chmin(T &a, T b){if (a > b){a = b;return true;}return false;}
template <class T = int>T gcd(T a, T b){return (b == 0) ? a : gcd(b, a % b);}
template <class T = int>T lcm(T a, T b){return a / gcd(a, b) * b;}
using P  = pair<int,int>;

const int MAXN = 50000010;

list<int> A(MAXN);
list<bool> isprime(MAXN,true);
list<int> CNT(MAXN,0);

void setup_init(){
    rep(i,MAXN){A[i]=i;}
    isprime[0] = isprime[1] = false;
    for (int i = 2; i < MAXN;i++){
        if (!isprime[i])continue;
        int sq = i*i;
        for (int j = 2*i; j < MAXN;j+=i){
            isprime[j]=false;
            while(A[j]%sq == 0){A[j]/=sq;}
        }
    }
}

signed main(){
    setup_init();
    int n;cin>>n;
    rep1(i,n){CNT[A[i]]++;}
    
    int ans = 0;
    rep1(i,n){
        ans += CNT[i]*CNT[i];
    }
    cout << ans << endl;
    return 0;
}