#include <iostream>
#include <fstream>
using namespace std;

int main()
{
    ifstream f("factorial.in");
    ofstream g("factorial.out");

    int p,i=0,n=0;

    f>>p;
    while(i<p)
    {
        if(n%5==0)
            i++;

        n+=5;
    }

    g<<n-5;
    return 0;
}