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