#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
#define REP(i, a, n) for(int i=a; i<n; i++)

vector<int> prime;
void crate_prime(int n) {
	vector<bool> p;
	p.resize(n + 1, true);
	p[0] = p[1] = false;
	for (int i = 2; i*i <= n; i++) {
		if (p[i]) {
			for (int j = 2 * i; j < n; j += i) p[j] = false;
		}
	}

	REP(i, 2, n+1) if (p[i]) prime.push_back(i);
}

int dp[2270][20101];
int main()
{
	int N;
	cin >> N;
	crate_prime(N+1);
	REP(i, 0, 2270) REP(j, 0, 20101) dp[i][j] = -1;

	dp[0][0] = 0;
	REP(i, 0, (int)prime.size()) {
		REP(j, 0, N + 1) {
			if (dp[i][j] >= 0) {
				dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);
				if(j+prime[i] < 20101) dp[i + 1][j + prime[i]] = max(dp[i + 1][j + prime[i]], dp[i][j] + 1);
			}
		}
	}

	cout << dp[(int)prime.size()][N] << endl;
	return 0;
}