#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,s=0; cin>>n>>m; int a[n][m]; for(int i=1;i<=n;i++){ for(int j=1;j<=m;j++){ cin>>a[i][j]; if(i==1||j==1||i==n||j==m){ s+=a[i][j]; } } } cout<<s; return 0; }