#!/usr/bin/env python3

import sys
import json

paths = sys.argv[1:]
json_paths = [x.replace(".jpeg", ".json").replace(".jpg", ".json") for x in paths]

def calculate_x(path):
    with open(path) as f:
        dct = json.loads(f.read())
    x_coords = [x for x, y in dct['shapes'][0]['points']]
    x = (min(x_coords) + max(x_coords))/2
    return x

for path in json_paths:
    print(calculate_x(path))
