var
    n,m,i,j,k,ans:longint;

function com(a,b:integer):longint;
var
    l,r:integer;
    f:array[1..50,0..50] of longint;
begin
    for l:=1 to a do
        begin
            f[l,0]:=1;
            f[l,1]:=1;
        end;
    for l:=2 to a do
        for r:=1 to b do
            f[l,r]:=f[l-1,r-1]+f[l-1,r];
    com:=f[a,b];
end;

function n_mi(x,y:integer):longint;
var
    c,d:integer;
begin
    d:=1;
    for c:=1 to y do
        d:=d*x;
    n_mi:=d;
end;

begin
    assign(input,'piggy.in');
    assign(output,'piggy.out');
    reset(input);
    rewrite(input);
    read(n,m);
    if n<m then
        begin
            ans:=0;
            write(ans);
            close(input);
            close(output);
            halt;
        end;
    ans:=0;
    for k:=0 to m-1 do
        begin
            if k mod 2=0 then
                ans:=ans+com(m,k)*n_mi(m-k,n)
                else
                   ans:=ans-com(m,k)*n_mi(m-k,n);
        end;
    write(ans);
    close(input);
    close(output);
end.