#include<bits/stdc++.h>
using namespace std;
unsigned long long n, m, a[10000][10000], ans;
int main() {
	cin >> m >> n;
	for (int i = 1; i <= m; i++) {
		for (int j = 1; j <= n; j++) {
			cin >> a[i][j];
		}
	}
	for (int i = 1; i <= n; i++) {
		ans += a[1][i];
		ans += a[m][i];
	}
	for (int i = 2; i < m; i++) {
		ans += a[i][1];
		ans += a[i][n];
	}
	cout << ans;
	return 0;
}