program Project2;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
  n:int64;
  s: double;
  i, k:integer;
begin
  readln(n,k);
  s:=1;
  for i:=1 to k do begin
    s:=s*((n-k+i) / i); //6
  end;
  writeln(s:1:0);
  readln;
  readln;
end.