#include <fstream>

using namespace std;

int putere(int x)
{
    int i=0;
    while(x!=1)
    {
        i++;
        x/=2;
    }
    return i;
}
int main()
{
    int p;
    ifstream fin("fact.in");
    ofstream fout("fact.out");
    fin>>p;
    if(p==0) fout<<1;
    else if(!(p%5))
        fout<<(p-putere(p/5) )*5;
    else if(p%5)
        fout<<p*5;
    else if(p%25==0) fout<<-1;
    return 0;
}