#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys

if len(sys.argv) != 3:
    print "Usage: %s filename mod-number" % (sys.argv[0])
    quit()

filename = sys.argv[1]
M = int(sys.argv[2])
i = 0
f = open(filename)
line = f.readline().rstrip()
while line:
    if (i % M) == 0:
        print line
    i += 1
    line = f.readline().rstrip()

f.close()