#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    ifstream in("fact.in");
    ofstream out("fact.out");
    unsigned p, nraux=5, nr5=1;
    in>>p;
    while(nr5<p)
    {
        nraux+=5;
        unsigned aux =nraux;
        while (aux%5==0)
        {
            nr5+=1;
            aux/=5;
        }
    }
    if(nr5==p)
        out<<nraux;
    else
        out<<"-1";
    return 0;
}