#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ int n,m,a[21][21],c=0; cin>>n>>m; for(int i=0;i<n;i++){ for(int j=0;j<m;j++){ cin>>a[i][j]; if(i==0||i==n-1){ c+=a[i][j]; } else if(j==0||j==m-1){ c+=a[i][j]; } } } cout<<c<<endl; return 0; }