#include <bits/extc++.h>
using namespace std;
const vector<int> dx = {0, 0, 1, -1};
const vector<int> dy = {1, -1, 0, 0};
#define vec vector
#define int long long
#define double long double
//cout<<setprecision(15)<<fixed<<..
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define req(i, x, n) for (int i = x; i < (int)(n); i++)
#define pii pair<int,int>
#define pq priority_queue
#define all(V) begin(V),end(V)
#define printpair(p) cout<<p.first<<" "<<p.second<<"\n"
#define tple tuple<int,int,int>
template<class T, class U> inline bool chmax(T &a, const U &b) { if (a < b) { a = b; return true; } return false; }
template<class T, class U> inline bool chmin(T &a, const U &b) { if (a > b) { a = b; return true; } return false; }
#define nexper(Z) next_permutation(all(Z))
#define pb push_back

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

    int n;
    cin>>n;
    vec<int> A={2,3,5,7,11,13,17,19,23,29,31,37,41,43,47};
    int cur=1,cnt=0;
    rep(i,15){
        if(cur*A[i]<=n){
            cur*=A[i];
            cnt++;
        }
    }
    cout<<cnt;

}