#include<bits/stdc++.h>
using namespace std;
using ll=long long;
constexpr int MOD=998244353;

int main(){
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  ll N;
  cin>>N;
  vector p={2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47};
  ll t=1;
  for(int i=0;i<(int)p.size();i++){
    t*=p[i];
    if(t>N){
      cout<<i<<'\n';
      return 0;
    }
  }
  cout<<p.size()<<'\n';
}