Love-Hate

Description:

Input:

The first line contains three integers $$$n, m$$$ and $$$p$$$ $$$(1 \le n \le 2 \cdot 10^5, 1 \le p \le m \le 60, 1 \le p \le 15)$$$, which is the number of trader friends, the number of currencies, the maximum number of currencies each friend can like.

Each of the next $$$n$$$ lines contain $$$m$$$ characters. The $$$j$$$-th character of $$$i$$$-th line is $$$1$$$ if friend $$$i$$$ likes the currency $$$j$$$ and $$$0$$$ otherwise. It is guaranteed that the number of ones in each line does not exceed $$$p$$$.

Output:

Print a string of length $$$m$$$, which defines the subset of currencies of the maximum size, which are liked by at least half of all friends. Currencies belonging to this subset must be signified by the character $$$1$$$.

If there are multiple answers, print any.

Sample Input:

3 4 3
1000
0110
1001

Sample Output:

1000

Sample Input:

5 5 4
11001
10101
10010
01110
11011

Sample Output:

10001

Note:

In the first sample test case only the first currency is liked by at least $$$\lceil \frac{3}{2} \rceil = 2$$$ friends, therefore it's easy to demonstrate that a better answer cannot be found.

In the second sample test case the answer includes $$$2$$$ currencies and will be liked by friends $$$1$$$, $$$2$$$, and $$$5$$$. For this test case there are other currencies that are liked by at least half of the friends, but using them we cannot achieve a larger subset size.