#include <iostream>
#include "math.h"
using namespace std;
int main() {
    // insert code here...
    float n;
    float threeNum,fiveNum;
    float fifteenNum;
    cin >> n;
    
    fifteenNum = floor(n/15);
    threeNum = floor(n/3) - fifteenNum;
    fiveNum = floor(n/5) - fifteenNum;
    
    float ans = 4 * fifteenNum + 2 * (threeNum + fiveNum);
    cout << ans <<endl;
    

    return 0;
}