a,b= map(int,input().split())
a = list(bin(a))
b = list(bin(b))
a = a[2:]
b=b[2:]
aa = 12 - len(a)
bb = 12 - len(b)
a.reverse()
b.reverse()
for i in range(12):
    if(aa):
        aa -= 1
        a.append('0')
    if(bb):
        bb -= 1
        b.append('0')
a.reverse()
b.reverse()
ans = [0]*12
for i in range(12):
    g = int(a[i]) ^ int(b[i])
    ans[i] = str(g)
aaa = ['0','b']
aaa.extend(ans)
ans = ''.join(aaa)
print(int(ans,base=2))