// Arhiva de probleme - Factoria;



var
        i, p, p5, x     : longint;
        f               : text;


begin
assign  (f, 'fact.in');
reset   (f);
readln  (f, p);
close   (f);


for i := 1 to 1 shl 31 - 1 do
    begin
    x := i;
    while (x mod 5 = 0) do
        begin
        x := x div 5;
        inc (p5);
        end;

    if (p5 >= p) then
        break;
    end;


assign  (f, 'fact.out');
rewrite (f);
writeln (f, i);
close   (f);
end.