#include <cmath>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <functional>
#include <queue>
#include <iostream>
#include <string.h>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <cstdint>
#include <climits>
#include <unordered_set>
#include <sstream>
#include <stack>

using namespace std;

typedef long long int ll;
typedef pair<int,int> pii;
typedef tuple<int,int,int> t3;

using namespace std;

int main(){
    ll n;
    cin >> n;
    double r2 = n/3.0;
    double r = sqrt(r2);
    cout << max((ll)1, (ll)round(r)) << endl;
    return 0;
}