# 입력
x = [
{'a':1, 'b':2, 'c':3, 'd':4},
{'a':4, 'b':5, 'c':6, 'd':7},
{'a':2, 'b':3, 'c':4, 'd':5},
]
print(', '.join(x[0].keys()))
print('\n'.join(', '.join(str(z) for z in y.values()) for y in x))
IyDsnoXroKUKeCA9IFsKICAgIHsnYSc6MSwgJ2InOjIsICdjJzozLCAnZCc6NH0sCiAgICB7J2EnOjQsICdiJzo1LCAnYyc6NiwgJ2QnOjd9LAogICAgeydhJzoyLCAnYic6MywgJ2MnOjQsICdkJzo1fSwKXQoKcHJpbnQoJywgJy5qb2luKHhbMF0ua2V5cygpKSkKcHJpbnQoJ1xuJy5qb2luKCcsICcuam9pbihzdHIoeikgZm9yIHogaW4geS52YWx1ZXMoKSkgZm9yIHkgaW4geCkp
a, b, c, d
1, 2, 3, 4
4, 5, 6, 7
2, 3, 4, 5