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