#!/usr/bin/python3

import json
import sys


def inputs(args):
    if args:
        for filename in args:
            with open(filename) as f:
                yield filename, f
    else:
        yield "-", sys.stdin


objs = []
for filename, f in inputs(sys.argv[1:]):
    objs.append(json.load(f))
json.dump(objs, sys.stdout, indent=4)
sys.stdout.write("\n")