n,k = map(int,input().split())
if k >= 4:print(("0"*k+"101100"*(n//6+2))[:n])
elif k == 3:print("00010111"[:n] if n <= 8 else -1)
elif k == 2:print("1100"[:n] if n <= 4 else -1)
else:print("10"[:n] if n <= 2 else -1)