1 #include<stdio.h>
 2 #include<iostream>
 3 #include<algorithm>
 4 #include<cstring>
 5 #include<cmath>
 6 #include<queue>
 7 #include<set>
 8 #include<map>
 9 #define Min(a,b)  a>b?b:a
10 #define Max(a,b)  a>b?a:b
11 #define CL(a,num)  memset(a,num,sizeof(a));
12 #define inf 9999999
13 #define maxn 400
14 #define mod (1000000000 + 7)
15 #define eps  1e-6
16 #define ll long long
17 using namespace std;
18 ll dp[maxn][maxn][2];//0 上 1 左
19 ll matu[maxn][maxn],matw[maxn][maxn];
20 int main()
21 {
22     int n,m,i,j,t1;
23     while(scanf("%d%d",&n,&m),n + m)
24     {
25         for(i = 1 ; i <= n; ++i)
26          for(j = 1; j <= m ; ++j)
27          {
28              scanf("%lld",&matw[i][j]);
29          }
30
31          for(i = 1;  i <= n ; ++i)
32          {
33              for(j = 1; j <= m ;++j)
34              scanf("%lld",&matu[i][j]);
35          }
36          CL(dp,0);
37
38          int sum = 0,k;
39          for( i = 1 ; i <= n ;++i)
40          {
41              for( j = 1; j <= m; ++j )
42              {
43                  sum = 0;
44                  for(k = i ; k >= 1; --k)sum += matu[k][j];
45
46                  dp[i][j][0] = sum + max(dp[i][j - 1][0],dp[i][j - 1][1]);
47
48                  sum = 0;
49                  for(k = j ;k >= 1; --k) sum += matw[i][k];
50
51                  dp[i][j][1] = sum + max(dp[i - 1][j][0],dp[i - 1][j][1]);
52
53              }
54          }
55
56          printf("%lld\n",max(dp[n][m][0],dp[n][m][1]));
57
58
59     }
60 }