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