import sys

sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# inf = (1 << 31)-1
# md = 10**9+7
md = 998244353

from collections import defaultdict

n, M = LI()
# lms = [(1, 1, 1)]
l = 0
st = [(1, 1)]
mxs = -1
ml = -1
while st:
    nst = []
    l += 1
    if l > n: break
    while st:
        mx, s = st.pop()
        if s > mxs or (s == mxs and l < ml): mxs, ml = s, l
        # lms.append((l, mx, s))
        if mx*2 <= M: nst.append((mx*2, s+mx*2))
        if mx > 1 and mx*2-1 <= M: nst.append((mx*2-1, s+mx*2-1))
    st = nst
# print(lms)
# print(mxs, ml)
print(mxs+n-ml)