纯暴力给解了

a,b=map(int ,input().split())
def number(x,y):#C x ,y
    n=1
    if x> y*0.5 :
        x=y-x
    for i in range(x):
        n=n*(y-i)
    for j in range(1,1+x):
        n=n//j
    return n

an=0
for i in range(b+1):
    ok = i-(b-i)
    if ok %a ==0:
        an=an+number(i,b)
print(an)