#include<bits/stdc++.h> using namespace std; int main() { int m, n, a[101][101], num = 0; 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 <= m; i++) { for (int j = 1; j <= n; j++) { if (i == 1 || j == 1 || i == m || j == n) num += a[i][j]; } } cout << num; return 0; }