Program factorial;
var p,s,k,l:integer;n:=1;f:=1;
    b:boolean;
    f1,f2:text;
    s1:string;
begin
b:=true;
assign(f1,'fact.in');assign(f2,'fact.out');
reset(f1);rewrite(f2);
read(f1,p);
if (p=0) then begin n:=1; b:=false; end;
while (b=true) do
begin
f*=n;
inc(n);
s:=f;
s1:=s.ToString;
if length(s1)>(p-1) then
begin
if s1[(length(s1)-(p-1))] = '0' then
begin
b:=false;
end;
end;


end;

write(f2,n);
close(f1);
close(f2);
end.