#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using ll =  long long ;
using P = pair<int,int> ;
const ll INF = 1e18;
const int MOD = 1000000007;

struct Sieve {
        int n;
        vector<ll> f,primes;
        
        Sieve(int n=1):n(n),f(n+1){
                f[0] = f[1] = -1;
                for(long long i=2;i<=n;++i){
                        if(f[i]) continue;
                        primes.push_back(i);
                        f[i] = i;
                        for(long long j = i*i;j <= n;j += i) {
                                if(!f[j]) f[j] = i;
                        }
                }
        }
        
        bool isPrime(ll x){return f[x] == x;}
        
        vector<int> factorList(int x){
                vector<int> res;
                while(x != 1){
                        res.push_back(f[x]);
                        x /= f[x];
                }
                return res;
        }
        
        vector<pair<int,int>> factor(int x){
                vector<int> fl = factorList(x);
                if(fl.size() == 0) return {};
                vector<pair<int,int>> res(1,pair<int,int>(fl[0],0));
                for(int p:fl){
                        if(res.back().first == p){
                                res.back().second ++;
                        }else{
                                res.emplace_back(p,1);
                        }
                }
                return res;
        }
        
};

int main(){
    Sieve sieve(500005);
    int n;
    cin >> n;
    ll ans = 0;
    for(ll r:sieve.primes){
        if(r * r > 2 * n) break;
        for(ll p:sieve.primes){
            if((r * r - p) < 0 ) break;
            if((r * r - p) > n) continue;
            if(r <= n && p <= n && sieve.isPrime(r * r - p)) ans++;
        }
    }
    cout << ans << endl;
    return 0;
}