#include<iostream>
using std::cin;
using std::cout;
long long a[1005][1005],n,m,sum;
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            cin>>a[i][j];
        }
    }
    for(int i=2;i<=n;i+=3){
        for(int j=2;j<=m;j+=3){
            sum+=a[i][j];
        }
    }
    cout<<sum;
    return 0;
}