#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

using LL = __int128_t;

istream &operator>>(istream &is, LL &x) {
    int c = is.peek();
    while (c == ' ' || c == '\n') {
        is.get();
        c = is.peek();
    }
    bool neg = false;
    if (c == '-') {
        neg = true;
        is.get();
    }
    x = 0;
    while (isdigit(is.peek())) {
        x = x * 10 + is.get() - '0';
    }
    if (neg) {
        x = -x;
    }
    return is;
}

ostream &operator<<(ostream &os, LL x) {
    if (x < 0) {
        os << '-';
        x = -x;
    }
    if (x == 0) {
        return os << '0';
    }
    string s;
    while (x > 0) {
        s += x % 10 + '0';
        x /= 10;
    }
    reverse(s.begin(), s.end());
    return os << s;
}

const vector<ll> primes = {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};

int main() {
    LL N;
    cin >> N;

    LL tmp = 1;
    int ans = 0;
    for (ll x : primes) {
        if (tmp * x > N) {
            cout << ans << endl;
            break;
        }
        tmp *= x;
        ans++;
    }
}