var p,n,zero,j:longint; 
    t,te:text;  
  
begin  
n:=0;   
  
assign(t,'fact.in'); reset(t);   
readln(t,p);   
while zero<p do  
  begin  
    n:=n+5;   
if n div 5 mod 5=0 then begin   j:=n;   
    while j mod 5 = 0 do  
      begin  
        zero:=zero+1;   
        j:=j div 5;   
      end;    end  
      else zero:=zero+1;   
  
  end;   
  
  
assign(te,'fact.out');  rewrite(te);   
if((zero<>0) and (zero=p)) then writeln(te,n)   
  else if zero>p then writeln(te,'-1')   
    else writeln(te,'1');   
close(te);   
end.