#include<fstream>
using namespace std;
int main()
{
	ifstream in ("fact.in");
	ofstream out("fact.out");
	long int p,nrtz,i,ii,p2=0;
	in>>p;
	nrtz=5*p;
	for (i=5;i<=nrtz-5;i+=5)
	{ii=i/5;
	if ((ii%5==0)&&(ii!=0)) while(ii!=0)
					{ if (ii%5==0) nrtz=nrtz-5;
					  ii=ii/5;
					}
	}
	if(nrtz%25==0)
		{for(i=5;i<=nrtz;i=i+5)
		 {ii=i;
		while (ii!=0)
			{if(ii%5==0)p2++;
			ii=ii/5;}
		 
		}
	if(p2==p)
	{		
	out<< nrtz;
	}
	}
	if (nrtz==0) nrtz =1;
	if (nrtz%25==0)nrtz=-1;
	out<< nrtz;
	in.close();
	out.close();
	return 0;
}