#include<iostream>
#include<fstream>
#include<vector>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
long long count_dem_zeros (long long a)
{
    long long i=5,nr=0;
    while(i<=a)
    {
        nr+=a/i;
        i*=5;
    }
    return nr;
}
long long cb(long long x)
{
    long long i=0,pas=2<<27;
    while(pas!=0)
    {
        if(count_dem_zeros(i+pas)<x)
            i+=pas;
        pas>>=1;
    }
    return i+1;
}
int main()
{
    long long  n;
    in>>n;
   long long f=cb(n);
    if(count_dem_zeros(f)==n)
        out<<f;
    else
        out<<"-1";
}