#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

#define fi first
#define se second
#define int long long
#define vec vector


using namespace std;

void solve()
{
    int n, m;
    cin>>n>>m;
    vec<vec<int>> a(n, vec<int>(m, 0));
    int sum = 0;
    for(int i = 0; i<n; i++)
        for(int j = 0; j<m; j++)
        {
            cin>>a[i][j];
            sum += a[i][j];
        }
    if(n % 2 || m % 2){
        cout << sum << "\n";
        return;
    }

    int ans = 0;

    int mi = 1e18;
    for(int i = 0;i<n;i++){
        for(int j = 0;j<m;j++){
            if((i + j) % 2 == 1){
                mi = min(a[i][j], mi);
            }
        }
    }

    cout << sum - mi << "\n";

}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int tests = 1;
    while(tests--)
    {
        solve();
    }

}