var
    i,j,k,n,m,pp,t:longint;
    f:array[1..1000,1..1000] of qword;
    p:array[1..55] of qword;
begin
      assign(input,'pigdy.in');
      reset(input);
      assign(output,'pigdy.out');
      rewrite(output);
      for i:= 1 to 55 do
      f[i,1]:=1;
      f[1,1]:=1;
      f[2,2]:=2;
      for i:=3 to 18 do
      begin
           for j:= 2 to 17 do
           f[i,j]:=(f[i-1,j]+f[i-1,j-1])*j;
      end;
      p[1]:=1;
      for i:=2 to 18 do
      p[i]:=p[i-1]*i;
      read(t);
      for pp:= 1 to t do
      begin
           read(n,m);
           if  m=n then
           writeln(1)
           else
           writeln(f[n,m] div p[m]);
      end;
      close(input);
      close(output);
end.