Use backward reasoning to solve this problem

Question 4. (12 pts) Find the weakest precondition for the following code. Show all intermediate conditions. Simplify your answer as much as possible. } // This is the weakest precondition. Please fill in. } // This is an intermediate condition. Please fill in. { x++; { if (z != 5) { { z = x + 1; { } // This is an intermediate condition. Please fill in. } // This is an intermediate condition. Please fill in. = } // This is an intermediate condition. Please fill in. z; { } { Z = y z; { z != 0 } } // This is an intermediate condition. Please fill in. // This is the postcondition