program factorial;
 var a,z,x,p:longint;
     f,g:text;
 begin
 assign (f,'fact.in');
 assign (g,'fact.out');
 reset (f);
 rewrite (g);
 read (f,p);
 repeat
 z:=z+5;
 a:=5;
 repeat
 if z mod a=0 then x:=x+1;
 a:=a*5;
 until z mod a<>0;
 until x>=p;
 if x>p then z:=-1;
 write (g,z);
 close (f);
 close (g);
 end.