#include <iostream>
#include <fstream>

using namespace std;

int fact(int a){
    long int rez=1;
    for (int i=1;i<=a;i++)
        rez=rez*i;
    return rez;
}

int main()
{
    ifstream in("fact.in");
    ofstream out("fact.out");

    int p;

    in>>p;

    if (p==0){
        out<<1;
        return 0;
    }

    int rez;
    for (int i=5;i<=p*5;i=i+5){
        rez=i;
    }
    out<<rez;

    in.close();
    out.close();
    return 0;
}