#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int main()
{
    int i,p,x,k=0;
    fin>>p;
    if(p==0)fout<<1;
    else
    {
        i=5;
        while(p>0)
        {
            x=p;
            p-=(i*5-i)/5+k*4;
            k++;
            i*=5;
        }
        i/=5;
        p=x;
        while(p>0)
        {
            x=i;
            while(x%5==0)
            {
                p--;
                x/=5;
            }
            i+=5;
        }
        i-=5;
        if(p==0)fout<<i;
        else fout<<-1;
    }
    return 0;
}