#include <bits/stdc++.h>
using namespace std;
int main() {
	int m,n;
	int sum = 0;
	cin >> m >> n;
	int s[105][105];
	for (int i = 1;i <= m; i++) {
		for (int j = 1;j <= n; j++) {
			cin >> s[i][j];
		}
	}
	for (int i = 1;i <= n; i++) {
		sum += s[1][i];
	}
	for (int i = 2;i <= m - 1; i++) {
		sum += s[i][1];
	}
	for (int i = 2;i <= m - 1; i++) {
		sum += s[i][n];
	}
	for (int i = 1;i <= n; i++) {
	   	sum += s[m][i];
	}
	cout << sum ;
	return 0;
}