#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int main()
{
    int p, n, i, cop;
    fin >> p;
    if(p==0)
        fout << "1";
    else
    {
        n=p*5;
        i=25;
        while(i<=n)
        {
            n-=5;
            i+=25;
        }
        fout << n;

    }
    return 0;
}