#include<fstream.h>

ifstream f("fact.in");
ofstream g("fact.out");


main()
{long long int N,P,i,j=0,k=1,p=0,c,d;
f>>P;

if(P==0)
{g<<'1';}
else{
c=P;
while(c>0)
{j=j+c/5;
c=c/5;}

for(i=0;i<=j;i++)
{p=0;
	N=5*(P-i);
d=N;
while(d>0)
{p=p+d/5;
d=d/5;}

if(p==P)
{g<<N;
k=0;
f.close();
g.close();}
}

if(k==1)
{g<<'-1';}}
}