#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 1000000000000000001

int main(){
   
   long long n;
   cin>>n;
   vector<long long> p = {2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97};
   
   long long ans = 0;
  rep(i,p.size()){
   if(n>=p[i]){
      n /= p[i];
   }
   else{
      cout<<i<<endl;
      return 0;
   }
  }
	return 0;
}