How to draw a rectangle on a specific object using OpenCV and Python

I want to wrap the rectangle in the first position (red 1), but when I use cv2.rectangle() to draw, I get 2 rectangles. When I adjusted the contrast (I just want to mark the center of the 1st rectangle) but I can't get rid of the yellow area (many more have been marked) like the image below:

Here is an original image when I run my code:

Original

here is what I want to get

Desired

contours, hierarchy = cv2.findContours(binary_img, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
for cntr in contours:
    x, y, w, h = cv2.boundingRect(cntr)
    rect_img = cv2.rectangle(img, (x, y), (x + w, y + h), (0, 0, 255), 2)

    # ----------put text on img
    cX = int(x + (w / 2))
    cY = int(y + (h / 2))


    img = cv2.rectangle(img, (x, y), (x + w, y + h), (0, 0, 255), 2)
    cv2.putText(img, "+", (cX, cY), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 255, 0), 1)

cv2.putText(rect_img, ("X = " + str(cX)), (5, 50), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (255, 255, 255), 1)
cv2.putText(rect_img, ("Y = " + str(cY)), (5, 70), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (255, 255, 255), 1)
cv2.imshow("img2", img)

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