program factorial;
var f,g:text;
    k,s,p,nr2,i:real;
begin
assign(f,'fact.in');assign(g,'fact.out');reset(f);rewrite(g);
read(f,k);
nr2:=0; i:=0;
if k>0 then begin
while nr2<k do begin
i:=i+1;
nr2:=0; p:=5;s:=0;
while trunc(i / p)<>0 do begin
s:=s+ trunc(i / p);
p:=p*5;end;
nr2:=s;
end;
if (nr2=k) then
write(g,i:0:0)
          else write(g,'-1');
end
else write(g,'1');
close(f);close(g);end.