#include<bits/stdc++.h>
#define int long long int
#define inf 100000000000000
#define IOS ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
int mod=998244353;
int arr[8][8];
int n,m;
void print()
{
for(int i=0;i<n;i++)
{
for(int j=0;j<m;j++)
{
cout<<arr[i][j]<<" ";
}
cout<<endl;
}
}
int32_t main()
{
IOS;
cin>>n>>m;
for(int i=0;i<n;i++)
{
for(int j=0;j<m;j++)
{
cin>>arr[i][j];
}
}
for(int j=0;j<m;j++)
{
for(int i=n-2;i>=0;i--)
{
arr[i][j]+=arr[i+1][j];
}
}
for(int i=0;i<n;i++)
{
for(int j=m-2;j>=0;j--)
{
arr[i][j]+=arr[i][j+1];
}
}
int ans=0;
int sum=arr[0][0];
for(int i=1;i<n;i++)
{
for(int j=1;j<m;j++)
{
if(arr[i][j]<=sum/2)
{
ans=max(ans,arr[i][j]);
}
}
}
cout<<sum-ans<<endl;
}
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