total = set() def combos(n,k, visited, record): global total if n == 0: if k == 0: total.add(record) return combos(n-1,k,False, record+"0") if not visited and k > 0: combos(n-1,k-1,True, record+"1") n = int(raw_input()) for x in range(n): xy = raw_input().split(" ") x,y = int(xy[0]), int(xy[1]) total = set() combos(x,y,False,"") print(len(total))