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

ifstream fin("fact.in");
ofstream fout("fact.out");

int main(){
    int n,k,p;
    fin>>p;
    n=5;k=0;
    while(p<=n){k=k+n/p;
                n=n*5;}
    fout<<n;
    return 0;
}