#include <iostream>
#include <vector>
#include <algorithm>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <random>
#include <iomanip>
#include <time.h>
#include <bitset>
#include <map>
#include <numeric>
#include <atcoder/modint>
#include <atcoder/dsu>
using namespace atcoder;
using namespace std;
using mint = modint998244353;
#define ll long long
#define pll pair<ll,ll>

ll n,prime[]={2,3,5,7,11,13,17,19,23,29,31,37,41,43,47},ans;

int main()
{
    cin >> n;
    for(int i=0;i<14;i++) prime[i+1]*=prime[i];
    for(int i=0;i<15;i++) if(n>=prime[i]) ans = i+1;
    cout << ans << endl;
}