#include <stdio.h>#include <string.h>#include <algorithm>#define clr(a,b) memset(a,b,sizeof(a))using namespace std;const int N = 310;const int inf = 0x3f3f3f3f;const int d = 100;int n, m, h, w;int mp[N][N], an[N][N];int cal(int x, int y){ int ans = -inf, t; for (int i=d+1; i<=n+d+h; i++) { for (int j=d+1; j<=m+d+w; j++) { t = mp[i][j]+mp[i-x][j-y]-mp[i-x][j]-mp[i][j-y]; if (ans < t) ans = t; } } return ans;}int main(){ while (~scanf("%d%d%d%d", &n,&m,&h,&w)) { clr(mp, 0); clr(an, 0); for (int i=101; i<=n+100; i++) for (int j=101; j<=m+100; j++) scanf("%d", &mp[i][j]), mp[i][j]+=mp[i-1][j]+mp[i][j-1]-mp[i-1][j-1]; for (int i=1+d; i<=n+d; i++) for (int j=m+1+d; j<=m+w+d; j++) mp[i][j]+=mp[i-1][j]+mp[i][j-1]-mp[i-1][j-1]; for (int i=n+d+1; i<=n+h+d; i++) for (int j=d+1; j<=m+w+d; j++) mp[i][j]+=mp[i-1][j]+mp[i][j-1]-mp[i-1][j-1]; int ans = -inf; for (int i=1; i<w; i++) an[h][i] = cal(h, i); for (int i=1; i<h; i++) an[i][w] = cal(i, w); for (int i=1; i<w; i++) ans = max(ans, an[h][i]+an[h][w-i]); for (int i=1; i<h; i++) ans = max(ans, an[i][w]+an[h-i][w]); printf("%dn", ans); } return 0;}
