#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
int main()
{
    int p,n,c=0,ok=1,i;
    in>>p;
    i=1;
    while(c>=p&&ok==1)
    {
        c=0;
        if(i%5==0)
        while(i%5==0)
        {
            c++;
        }
            i=i+5;
            if(c==p)
            {n=i;ok=0;}

    }
    out<<n;
    return 0;
}