#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int main() {
    int n;
    cin>>n;
    bool isp[n+1];
    fill(isp,isp+n+1,true);
    isp[0]=isp[1]=false;
    vector<int> ps;
    for (int i=2;i<=n;i++) {
        if (isp[i]) {
            ps.push_back(i);
            for (int j=i+i;j<=n;j+=i)
                isp[j]=false;
        }
    }
    int ans=0;
    for (int r:ps) {
        if (r*r>2*n)
            break;
        for (int p:ps) {
            int q=r*r-p;
            if (q<0) break;
            if (isp[q])
                ans++;
        }
    }
    cout<<ans<<endl;
    return 0;
}