package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var wr = bufio.NewWriter(os.Stdout)

func out(x ...interface{}) {
	fmt.Fprintln(wr, x...)
}

func getI() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func getF() float64 {
	sc.Scan()
	i, e := strconv.ParseFloat(sc.Text(), 64)
	if e != nil {
		panic(e)
	}
	return i
}

func getInts(N int) []int {
	ret := make([]int, N)
	for i := 0; i < N; i++ {
		ret[i] = getI()
	}
	return ret
}

func getS() string {
	sc.Scan()
	return sc.Text()
}

// min, max, asub, absなど基本関数
func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func asub(a, b int) int {
	if a > b {
		return a - b
	}
	return b - a
}

func abs(a int) int {
	if a >= 0 {
		return a
	}
	return -a
}

func lowerBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] >= x
	})
	return idx
}

func upperBound(a []int, x int) int {
	idx := sort.Search(len(a), func(i int) bool {
		return a[i] > x
	})
	return idx
}

func prime(N int) map[int]bool {
	a := make([]bool, N+1)
	for i := 2; i*i <= N; i++ {
		for j := i * 2; j <= N; j += i {
			a[j] = true
		}
	}
	ret := make(map[int]bool)
	for i := 2; i <= N; i++ {
		if a[i] == false {
			ret[i] = true
		}
	}

	return ret
}

func main() {
	defer wr.Flush()
	sc.Split(bufio.ScanWords)
	sc.Buffer([]byte{}, 1000000)
	// this template is new version.
	// use getI(), getS(), getInts(), getF()
	N := getI()
	x := prime(N)

	r2 := make(map[int]bool)
	for r := range x {
		if r*r > 2*N {
			continue
		}
		r2[r*r] = true
	}

	cnt := 0
	for r := range r2 {
		for p := range x {
			if r-p < 0 {
				continue
			}
			if x[r-p] == true {
				cnt++
			}
		}
	}
	out(cnt)
}