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