import sys
from itertools import zip_longest
def grouper(iterable, n, fillvalue=None):
"Collect data into fixed-length chunks or blocks"
# grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx"
args = [iter(iterable)] * n
return zip_longest(*args, fillvalue=fillvalue)
m = 3
file = sys.stdin
output_file = sys.stdout
for words in grouper(file, m, fillvalue=''):
print(*map(str.strip, words), file=output_file)
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