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