Cities in Alberta tend to be laid out as rectangular grids of blocks. Blocks are labeled with coordinates ~0~ to ~R-1~ from north to south and ~0~ to ~C-1~ from west to east.

The quality of living in each particular block has been ranked by a distinct number, called quality rank, between ~1~ and ~R \cdot C~, where ~1~ is the best and ~R \cdot C~ is the worst.

The city planning department wishes to identify a rectangular set of blocks with dimensions ~H~ from north to south and ~W~ from west to east, such that the median quality rank among all blocks in the rectangle is the best. ~H~ and ~W~ are odd numbers not exceeding ~R~ and ~C~ respectively. The median quality rank among an odd number of quality ranks is defined to be the quality rank ~m~ in the set such that the number of quality ranks better than ~m~ equals the number of quality ranks worse than ~m~.

Input Specification

The first line of input will contain the four space-separated integers ~R~, ~C~, ~H~, and ~W~, where ~R~ and ~C~ represent the total size of the city, and ~H~ and ~W~ represent the dimensions of the set of blocks.

The next ~R~ lines each contain ~C~ integers, denoting an array ~Q~ such that ~Q[a][b]~ is the quality rank for the block labeled ~a~ from north to south and ~b~ from west to east.

Output Specification

A single integer, the best (numerically smallest) possible median quality rank of an ~H~ by ~W~ rectangle of blocks.

Sample Input 1

5 5 3 3
5 11 12 16 25
17 18 2 7 10
4 23 20 3 1
24 21 19 14 9
6 22 8 13 15

Sample Output 1

9

Explanation for Sample Output 1

R=5, C=5, H=3, W=3,
Q=  5 11 12 16 25
   17 18  2  7 10
    4 23 20  3  1
   24 21 19 14  9
    6 22  8 13 15

For this example, the best (numerically smallest) median quality rank of ~9~ is achieved by the middle-right rectangle of ~Q~ shown in bold.

Sample Input 2

2 6 1 5
6 1 2 11 7 5
9 3 4 10 12 8

Sample Output 2

5

Subtask 1 [20 points]

Assume ~R~ and ~C~ do not exceed ~30~.

Subtask 2 [20 points]

Assume ~R~ and ~C~ do not exceed ~100~.

Subtask 3 [20 points]

Assume ~R~ and ~C~ do not exceed ~300~.

Subtask 4 [20 points]

Assume ~R~ and ~C~ do not exceed ~1\,000~.

Subtask 5 [20 points]

Assume ~R~ and ~C~ do not exceed ~3\,000~.