#include<bits/stdc++.h>
using namespace std;
#define ALL(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define INF 1000000000
#define mod 1000000007
using ll=long long;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

vector<int> sieve(int n){
    vector<int> ret(n+1,true);
    ret[0]=false;
    if(n>0) ret[1]=false;
    for(int i=2;i*i<=n;i++){
        if(!ret[i]) continue;
        for(int j=i*2;j<=n;j+=i) ret[j]=false;
    }
    return ret;
}

ll cnt[300000],ans;

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    auto isp=sieve(300000);
    vector<int> ps;
    rep(i,300000)if(isp[i])ps.push_back(i);
    


    int n;cin>>n;
    for(int i=0;ps[i]<=n;i++){
        int c=ps[i];

        rep(j,ps.size()){
            int sum=ps[j];
            if(sum-c>=0) ans+=cnt[sum-c];
        }

        rep(j,i) cnt[c+ps[j]]++;
    }
    cout<<ans<<endl;
    return 0;
}