import java.io.InputStream;
import java.io.PrintWriter;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.PriorityQueue;
import java.util.Scanner;
import java.util.Set;
import java.util.Stack;
import java.util.TreeMap;
import java.util.TreeSet;

import static java.util.Comparator.*;

public class Main {
    public static void main(String[] args) {
        PrintWriter out = new PrintWriter(System.out);
        Solver solver = new Solver(System.in, out);
        solver.solve();
        out.close();
    }
}
class Solver {
	Scanner sc;
	PrintWriter out;
    public Solver(InputStream in, PrintWriter out) {
    	sc = new Scanner(in);
    	this.out = out;
    }
    // ==================================================================
    // エラトステネスの篩(ふるい）　→　素数の表を作る（大体　O(N) らしい）								
    boolean[] arr = new boolean[500100];		// 初期値 false(素数なら false となる)			
    void eratosthenes(long n){								
    	arr[0] = arr[1] = true;					// 素数でない			
    	for(int i = 2; i * i <= n; i++){							
   		 if( !arr[i] ) {						
    			for(int j = i + i; j <= n; j += i){		// j は i の倍数となる		
   				 arr[j] = true;					// i の倍数は素数でない		
    			}					
    		}						
    	}							
    }
    Set<Integer> setR = new TreeSet<>();
    Set<Integer> setP = new TreeSet<>();
    public void solve() {
    	long N = Integer.parseInt(sc.next());
    	eratosthenes(N);
    	for (int i = 0; i * i <= 2*N; i++) {
			if(!arr[i])		setR.add(i);
		}
    	for (int i = 0; i <= N; i++) {
			if(!arr[i])		setP.add(i);
		}
    	int cnt = 0;
    	long wk;
    	for (int r : setR) {
			wk = (long)r * r;
			for (int p : setP) {
				if(wk - p > N)		continue;
				if(wk - p < p)		break;
				if(wk - p == p)							cnt++;
				else if(setP.contains((int)(wk - p))) 	cnt += 2;
			}
		}
    	out.println(cnt);
    }
    // ==================================================================
}