#include <fstream>
#include <math.h>
using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
unsigned long int N,P,numar;
unsigned int nr;
int main()
{
    f>>P;
    N=P*5-numar;
    nr=10;
    while(nr<N)
        {
            N-=(N%(nr+1)/nr*5);
            nr++;
        }
    N-=numar;
    g<<N;
    f.close();
    g.close();
}