Symmetric Encryption

Consider the following definition of a hash function based on a cryptographic algorithm. Let

$K$ be a given cryptographic key and $M=M_1{M}_{2}cdots{M}_n($with $n1)$ be a message where

$M_1,dots{M}_n$ are blocks of the same length:

$H(M_1)=E(K,M_1)$

$H(M_{1}cdots{M}_i{M}_{i+1})=E(K,H(M_{1}cdots{M}_i)o+M_{i+1})$ for $i=1,$dots,$n-1$

The schema is not secure$.$ Show that given a message $A_1{A}_2$ and an arbitrary block $B_1$ it is

possible to determine a block $B_2$ such that $H(B_1{B}_2)=H(A_1{A}_2),$ i$.$e$.H$ is not weak collision

resistant.