#include <bits/stdc++.h>
using namespace std;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);


    vector<int> factor = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59};
    long long n;
    cin >> n;
    int ans = 0;
    long long num = 1;
    for (int i = 0; i < factor.size(); i++){
        if (n/num < factor[i]){
            cout << i << endl;
            break;
        }
        num *= factor[i];
    }

    

    return 0;
}