var p,n,i:longint;

function div5(x:longint):byte;
begin
 if (x mod 5<>0) or (x=0) then div5:=0
                          else div5:=div5(x div 5)+1;
end;

begin
assign(input,'fact.in');reset(input);
assign(output,'fact.out');rewrite(output);
 readln(p);
 n:=5; dec(p);
 while p>0 do begin
  i:=div5(n);
  n:=n+i*5;
  p:=p-i;
 end;
if p<>0 then n:=n-abs(p)*5
        else n:=n-5;
write(n);
close(input);close(output);
end.