var n,k,p:qword;
    i:longint;
    f:text;
begin
assign(f,'sandokan.in');reset(f);
read(f,n,k); {
for i:=1 to n do read(f,a[i]);   }
close(f);
p:=1;
for i:=n-k+1 to n do p:=p*i;
for i:=2 to k do p:=p div i;
assign(f,'sandokan.out');rewrite(f);
write(f,p);
close(f);
end.