#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;
    if(P==0)
    {
        fout<<1;
    }
    else
    {
        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;
}