#include <iostream>
#include <stdio.h>
using namespace std;

int main()
{
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
    int n,p,z,x,a;
    cin>>p;
    if (p==0)
    {
        cout<<1;
    }
    else
    {
        n=5;
        z=1;
        while (z<p)
        {
            n=n+5;
            a=n;
            x=0;
            while (a%5==0)
            {
                a=a/5;
                x++;
            }
            z=z+x;
        }
        if (z>p)
        {
            cout<<-1;
        }
        else
        {
            cout<<n;
        }
    }
}