#include<bits/stdc++.h> using namespace std; int main() { int n,m,a[21][21],sum=0; cin>>n>>m; for(int i=1;i<=n;i++){ for(int j=1;j<=m;j++){ cin>>a[i][j]; if(i==1 || i==n) sum+=a[i][j]; else if(j==1 || j==m) sum+=a[i][j]; } } cout<<sum<<endl; return 0; }