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