{se da un numar p. Sa se gaseasca cel mai mic numar natural strict pozitiv
n pentru care N! are exact P cifre de 0 la sfarsit.}

program _factorial;

var p,n,i:integer;

function factorial(n:integer):integer;
var i,x:integer;
begin
     x:=1;
     for i:=1 to n do
         x:=x*i;
     factorial:=x;
end;

function cifre(n:integer):integer;
var i:integer; x:integer;
begin
     x:=0;
     while n<>0 do
     begin
          x:=x+1;
          n:=n div 10;
     end;
     cifre:=x;
end;

begin
     readln (p);
     n:=0;
     writeln (factorial(10));
     for i:=1 to 1000 do
         begin
              n:=n+1;
              if cifre(factorial(n))=p then
              begin
                    write (n);
                    break;
              end;
         end;
      readln;
end.