def main():
# Get the first input before the loop
num = float(input("Enter a positive number: "))
while num <= 0:
# We only execute the body if the input was not positive.
print("That number is not positive.")
# Get the input for the next iteration.
num = float(input("Enter a positive number: "))
# Once we get here, we know the condition is false,
# so the number must be positive.
print("Thank you for entering", num)
main()