N, M = map(int, input().split())

sum_total = 0
current = 1

for step in range(1, N + 1):
    remaining = N - step
    if remaining >= 30:
        max_x = 1
    else:
        power = 1 << remaining  # 2^remaining
        max_x = (M + power - 1) // power
    next_val = min(2 * current, max_x)
    sum_total += next_val
    current = next_val

print(sum_total)