#include<bits/stdc++.h>
using namespace std;
#define int long long
int n,m,a[205][205],ans;
vector<int>x,y;
signed main(){
	cin>>n>>m;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=m;j++)
			cin>>a[i][j];
	if(n%3==0){
		for(int i=2;i<=n;i+=3)
			x.push_back(i);
	}
	else if(n%3==1){
		x.push_back(1),x.push_back(n);
		for(int i=4;i<n;i+=3)
			x.push_back(i);
	}
	else{
		x.push_back(1);
		for(int i=4;i<=n;i+=3)
			x.push_back(i);
	}
	if(m%3==0){
		for(int i=2;i<=m;i+=3)
			y.push_back(i);
	}
	else if(m%3==1){
		y.push_back(1),y.push_back(m);
		for(int i=4;i<m;i+=3)
			y.push_back(i);
	}
	else{
		y.push_back(1);
		for(int i=4;i<=m;i+=3)
			y.push_back(i);
	}
	for(auto &&i:x)
		for(auto &&j:y)
			ans+=a[i][j];
	printf("%lld",ans);
	return 0;
}