def foo(n, i, j):
	j -= 1
	a = [0] * n
	a[j] = 1
	
	while i < n:
		next = [0] * n
		for k in range(n):
			if k == 0:
				next[k] = a[k + 1]
			elif k == n - 1:
				next[k] = a[k - 1]
			else:
				next[k] = a[k - 1] + a[k + 1]
		
		a = next
		i += 1
	
	return sum(a)
	
print(foo(8, 6, 3))