NGM2 - Another Game With Numbers

Little Chikoo likes to play with numbers. Often he plays the following game:

  1. He chooses a number N and a set of positive integers.
  2. He writes down all the numbers from 1 to N.
  3. He chooses the first number (say x) from the set and cancels out all the multiples of x from 1 to N, including x.
  4. He repeats step 3 for all the numbers from the set.

One day Little Chikoo was in a mood to play pranks. So his brother asked him to play the game with a certain challenge. He made the game a little harder and asked him to find out the number of integers which aren't cancelled after he completes step 4. If he does that then Little Chikoo gets to play on his brother's Nintendo for one full day. Now Little Chikoo is in a hurry and wants to finish the job as soon as possible. He has asked for your help.


The first line of the input contains N and K. (N <= 10^9, K <= 15)

Then K numbers follow all in a single line. All numbers are <= 100.


The output file must contain the number of integers that aren't cancelled after he finishes step 4 of the game.


10 3
2 4 5


(The numbers 1, 3, 7 and 9 weren't cancelled).

hide comments
Thomas: 2012-06-12 08:37:45

Does Someone knows the formula??

Gunjit : 2012-05-14 18:42:02

after running 23 test cases the judge says WA ... can any1 help me plz

accept: 2011-12-09 10:26:15

can anybody help me about runtime error (SIGSEGV)

sesume uchiha: 2011-07-31 07:51:36

@paranoid : can u help me with the test case for which my code is failing (id 5453378)

Last edit: 2011-07-31 08:28:10
anubhav gupta: 2011-07-14 11:20:52

@paranoid please check solution id 5378282 its giving wa.dont know why

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