#include <iostream>
#include <fstream>
#include <math.h>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");

int n, p, cont;



int main()
{
    int x=5;
    in>>p;
    if(p==0){
        out<<1;
    }else{
        while(cont<p){
            for(int i=10;i>=1;i--){
                if(x%int(pow(5, i))==0){
                    cont+=i;
                    //cout<<x<<" "<<pow(5, i)<<" "<<cont<<" "<<endl;

                    break;
                }
            }
            x+=5;
        }
    }
    out<<x-5;

}