T151T2

#include<bits/stdc++.h>

using namespace std;

#define gc c=getchar()
#define r(x) read(x)
#define ll long long

template<typename T>
inline void read(T&x){
    x=0;T k=1;char gc;
    while(!isdigit(c)){if(c=='-')k=-1;gc;}
    while(isdigit(c)){x=x*10+c-'0';gc;}x*=k;
}

const int N=2e6+7;

int tot;
int pri[N];
bool mark[N];

inline void pre(int n){
    for(int i=2;i<=n;++i){
        if(!mark[i])pri[++tot]=i;
        for(int j=1;j<=tot;++j){
            int tmp=i*pri[j];
            if(tmp>n)break;
            mark[tmp]=1;
            if(i%pri[j]==0)break;
        }
    }
}

inline int qpow(ll a,int b,int p){
    ll ans=1;
    while(b){
        if(b&1)(ans*=a)%=p;
        (a*=a)%=p;
        b>>=1;
    }
    return ans;
}

inline int get(int p){
    for(int i=2;i<p;++i){
        if(qpow(i,(p-1)/2,p)==p-1){
            return qpow(i,(p-1)/4,p);
        }
    }
}

bool vis[N];
ll f[N];

int main(){
    freopen("rauchen.in","r",stdin);
    freopen("rauchen.out","w",stdout);
    int n;r(n);
    pre(2*n);
    ll ans=0;
    for(int i=0;i<=n;++i){
        f[i]=(ll)4*i*i+1;
    }
    for(int i=2;i<=tot;++i){
        int p=pri[i];
        if(p%4!=1)continue;
        int rt=get(p);
        assert((ll)rt*rt%p==p-1);
        for(int k=(ll)(p+1)/2*rt%p;k<=n;k+=p){
            while(f[k]>p&&f[k]%p==0)f[k]/=p;
            if(f[k]==p){
                ans+=p;
                f[k]=1;
            }
        }
        rt=p-rt;
        for(int k=(ll)(p+1)/2*rt%p;k<=n;k+=p){
            while(f[k]>p&&f[k]%p==0)f[k]/=p;
            if(f[k]==p){
                ans+=p;
                f[k]=1;
            }

        }
    }
    for(int i=1;i<=n;++i){
        if(f[i]!=1)ans+=f[i];
    }
    printf("%lld\n",ans);
    return 0;
}