#include <iostream>
#include <fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
int DCO5(int x)
{
    int cont=0;
    while(x%5==0)
    {
        x/=5;
        ++cont;
    }
    return cont;
}
int main()
{
    int P,i,rez=0,cont=0;
    in>>P;
    if(P==0)
    {
        out<<1;
        return 0;
    }
    while(cont<P)
    {
        rez+=5;
        cont+=DCO5(rez);
    }
    if(cont==P) out<<rez;
    else out<<-1;
    return 0;
}