<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Write a code to find the missing number in the given array.
A = [1, 2, 3, 4, 6, 7, 8]<|im_end|>
<|im_start|>assistant
# Create a set from the array
A_set = set(A)

# Determine the max value
max_val = max(A_set)

# Find the missing number
missing_number = max_val - sum(A_set)

print(missing_number) # prints 5<|im_end|>
