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

int main()
{
long long p,n,a;
ifstream fin("fact.in");
ofstream fout("fact.out");
fin>>p;
n=5*p;
for (int i=1;i<=p;i++)
{
    if(n>25*i)
    {
        n=n-i*5;
    }
}
if (n==0)
    n++;
fout<<n;


}