program p1258;
 uses math;
 type arr=array[1..100]of longint;
 var n,k,i,j,l:longint;
     f:array[1..100,1..100]of arr;
  function time(p:arr;o:longint):arr;
   var c:arr;
       i:longint;
    begin
     fillchar(c,sizeof(c),0);
     for i:=1 to 99 do
      begin
       c[i]:=c[i]+p[i]*o;
       c[i+1]:=c[i] div 10;
       c[i]:=c[i] mod 10;
      end;
     exit(c);
    end;
  function add(p,o:arr):arr;
   var c:arr;
       i:longint;
    begin
     fillchar(c,sizeof(c),0);
     for i:=1 to 99 do
      begin
       c[i]:=c[i]+p[i]+o[i];
       c[i+1]:=c[i] div 10;
       c[i]:=c[i] mod 10;
      end;
     exit(c);
    end;
  begin
   assign(input,'k.in');
   reset(input);
   assign(output,'k.out');
   rewrite(output);
   read(n,k);
   for i:=1 to n do
    f[i,1][1]:=1;
   for i:=1 to n do
    for j:=2 to min(k,i) do
     f[i,j]:=add(time(f[i-1,j-1],(i-j+1)),time(f[i-1,j],j));
   l:=100;
   while (f[n,k][l]=0)and(l>1) do dec(l);
    for i:=l downto 1 do
     write(f[n,k][i]);
   close(input);
   close(output);
  end.