#include <iostream>
#include <fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
int main()
{
    int n;
    in>>n;
    if(n==0)
        out<<1;
    else
    {
        int nr=5,zero=0; //numar nr de zerouri in functie de M5
        while(zero<n)
        {
            int cop=nr;
            while(cop%5==0)
            {
                ++zero;
                cop=cop/5;
            }
            nr=nr+5;
            //cout<<nr<<" ";
        }
        nr=nr-5;
        out<<nr;
    }
    return 0;
}