def largestSubmatrixWithSumZero(mat, r, c):
	def find(arr):
		d={0:-1}
		t,ans=0,0
		for i in range(c):
			t+=arr[i]
			if t in d:ans=max(ans,i-d[t])
			else:d[t]=i
		return ans
	ans=float('-inf')
	for i in range(r):
		arr=[0]*c
		for j in range(i,r):
			for col in range(c):
				arr[col]+=mat[j][col]
			h=j-i+1
			w=find(arr)
			ans=max(ans,h*w)
	return ans


class Solution:
    def maximumSumRectangle(self,n,m,M):
        def kadane(arr):
            cursum,maxsum=0,float('-inf')
            for i in range(m):
                cursum+=arr[i]
                maxsum=max(maxsum,cursum)
                if cursum<0:cursum=0 
            return maxsum
                    
        maxsum=float('-inf')
        for i in range(n):
            arr=[0]*m
            for j in range(i,n):
                for k in range(m):
                    arr[k]+=M[j][k]
                t=kadane(arr)
                #print(t)
                maxsum=max(maxsum,t)
                
        return maxsum