#include <fstream>
 
using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int n, fact, aux, sw,k;
int main()
{
    fin>>n;
    if(n==0) k=1;
 
 
    while(n>0)
    {
        sw=0;
        fact=fact+5;
        aux=fact;
        while(aux%5==0)
            {aux=aux/5; sw++;}
        n=n-sw;
 
    }
 
        if(n==0&&k==0)fout<<fact;
        else if(k==1) fout<<"1";
        else fout<<"-1";
 
    return 0;
}