Suppose that
f : {0, 1}m {0 1}m is a preimage resistant
bijection. Define
h : {0, 1}2m {0, 1}m as follows. Given x OE {0, 1}2m, write x = x || x
where
x, x OE {0, 1}m. Then define

h
(x) = f (x'!x''). where is XOR operationProve that h is not second

preimage resistant.

could you please help me to prove that, any help would be appreciated
Thanks,