program fact;
var f,g:text;
    i,n,q:longint;
    ok:boolean;

function desc(x,y:longint):longint;
var w,nr:longint;
begin
w:=y;nr:=0;
while w>1 do
begin
nr:=nr+x div w;
w:=w div 5;
end;
desc:=nr;
end;




begin
assign(f,'fact.in');
assign(g,'fact.out');
reset(f);
rewrite(g);
read(f,n);
q:=5;
while desc(q*5,q*5)<n do
q:=q*5;
i:=desc(q*5,q*5);
if i=n then begin write(g,q*5); ok:=true; end;
i:=q+5;

if (desc(q*5-5,q)<n) and not ok then begin write(g,-1);ok:=true; end;

while (i<=q*5-5) and not ok do
if desc(i,q)=n then begin ok:=true; write(g,i); break; end else i:=i+1;


close(f);
close(g);
end.