#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
using namespace std;

typedef long long ll;

vector<int> prime;
bool isPrime[20020];
int makePrime(){
  for(int i = 0; i < 20020; i++){
    isPrime[i] = true;
  }
  for(int i = 2; i < 20020; i++){
    if(!isPrime[i]) continue;
    prime.push_back(i);
    for(int j = i; j < 20020; j += i){
      isPrime[j] = false;
    }
  }
  return prime.size();
}
int dp[5000][20020];
int main(){
  int n;
  cin >> n;
  int sz = makePrime();

  for (int i = 0; i < sz + 1; i++){
    for (int j = 0; j < 20020; j++){
      dp[i][j] = -1;
    }
  }
  dp[0][0] = 0;
  for (int i = 0; i < sz; i++){
    for (int j = 0; j < 20020; j++){
      if(dp[i][j] == -1) continue;
      dp[i+1][j] = max(dp[i+1][j], dp[i][j]);
      if(j+prime[i] >= 20020) continue;
      dp[i+1][j+prime[i]] = max(dp[i][j+prime[i]], dp[i][j]+1);
    }
  }

  printf("%d\n", dp[sz][n]);
  return 0;
}