#include<bits/stdc++.h>
using namespace std;

int dp[200][200][200];
int a, b;
int c[200][200];
int dx[2] = { -1,0 }, dy[2] = { 0,-1 };
int saiki(int d, int e, int f, int g) {
	if (dp[d][e][f] != -1)return dp[d][e][f];
	for (int h = 0; h < 2; h++) {
		for (int i = 0; i < 2; i++) {
			int n = d + dx[h], m = e + dy[h];
			if (n < 0 || m < 0)continue;
			int x = f + dx[i], y = g + dy[i];
			if (x < 0 || y < 0)continue;
			int S = saiki(n, m, x, y);
			S += c[d][e]; S += c[f][g];
			if (d == f&&e == g)S -= c[d][e];
			dp[d][e][f] = max(dp[d][e][f], S);
		}
	}
	return dp[d][e][f];
}
signed main() {
	memset(dp, -1, sizeof(dp));
	scanf("%d%d", &a, &b);
	for (int d = 0; d < a; d++) {
		for (int e = 0; e < b; e++) {
			scanf("%d", &c[d][e]);
		}
	}
	dp[0][0][0] = c[0][0];
	printf("%d\n", saiki(a - 1, b - 1, a - 1, b - 1));
}
### Prompt

Please formulate a CPP solution to the following problem:

Input

The input is given from standard input in the following format.


> $H \ W$ $a_{1, 1} \ a_{1, 2} \ \cdots \ a_{1, W}$ $a_{2, 1} \ a_{2, 2} \ \cdots \ a_{2, W}$ $\vdots \ \ \ \ \ \ \ \ \ \ \vdots \ \ \ \ \ \ \ \ \ \ \vdots$ $a_{H, 1} \ a_{H, 2} \ \cdots \ a_{H, W}$

Output

* Print the maximum number of souvenirs they can get.



Constraints

* $1 \le H, W \le 200$
* $0 \le a_{i, j} \le 10^5$



Subtasks

Subtask 1 [ 50 points ]


* The testcase in the subtask satisfies $1 \le H \le 2$.

Subtask 2 [ 80 points ]


* The testcase in the subtask satisfies $1 \le H \le 3$.

Subtask 3 [ 120 points ]


* The testcase in the subtask satisfies $1 \le H, W \le 7$.

Subtask 4 [ 150 points ]


* The testcase in the subtask satisfies $1 \le H, W \le 30$.

Subtask 5 [ 200 points ]


* There are no additional constraints.

Output

* Print the maximum number of souvenirs they can get.



Constraints

* $1 \le H, W \le 200$
* $0 \le a_{i, j} \le 10^5$



Subtasks

Subtask 1 [ 50 points ]


* The testcase in the subtask satisfies $1 \le H \le 2$.

Subtask 2 [ 80 points ]


* The testcase in the subtask satisfies $1 \le H \le 3$.

Subtask 3 [ 120 points ]


* The testcase in the subtask satisfies $1 \le H, W \le 7$.

Subtask 4 [ 150 points ]


* The testcase in the subtask satisfies $1 \le H, W \le 30$.

Subtask 5 [ 200 points ]


* There are no additional constraints.

Input

The input is given from standard input in the following format.


> $H \ W$ $a_{1, 1} \ a_{1, 2} \ \cdots \ a_{1, W}$ $a_{2, 1} \ a_{2, 2} \ \cdots \ a_{2, W}$ $\vdots \ \ \ \ \ \ \ \ \ \ \vdots \ \ \ \ \ \ \ \ \ \ \vdots$ $a_{H, 1} \ a_{H, 2} \ \cdots \ a_{H, W}$

Examples

Input

3 3
1 0 5
2 2 3
4 2 4


Output

21


Input

6 6
1 2 3 4 5 6
8 6 9 1 2 0
3 1 4 1 5 9
2 6 5 3 5 8
1 4 1 4 2 1
2 7 1 8 2 8


Output

97

### Response

```cpp
#include<bits/stdc++.h>
using namespace std;

int dp[200][200][200];
int a, b;
int c[200][200];
int dx[2] = { -1,0 }, dy[2] = { 0,-1 };
int saiki(int d, int e, int f, int g) {
	if (dp[d][e][f] != -1)return dp[d][e][f];
	for (int h = 0; h < 2; h++) {
		for (int i = 0; i < 2; i++) {
			int n = d + dx[h], m = e + dy[h];
			if (n < 0 || m < 0)continue;
			int x = f + dx[i], y = g + dy[i];
			if (x < 0 || y < 0)continue;
			int S = saiki(n, m, x, y);
			S += c[d][e]; S += c[f][g];
			if (d == f&&e == g)S -= c[d][e];
			dp[d][e][f] = max(dp[d][e][f], S);
		}
	}
	return dp[d][e][f];
}
signed main() {
	memset(dp, -1, sizeof(dp));
	scanf("%d%d", &a, &b);
	for (int d = 0; d < a; d++) {
		for (int e = 0; e < b; e++) {
			scanf("%d", &c[d][e]);
		}
	}
	dp[0][0][0] = c[0][0];
	printf("%d\n", saiki(a - 1, b - 1, a - 1, b - 1));
}
```